MGS V: The Phantom Pain FOB Staff Guide: How To Get Best Rank Soldiers and many more

This Guide covers the complete details on the staff management in Metal Gear Solid V: The Phantom Pain which you extract them to Mother Base and how to use them according to their rank, medal, moral etc. If you're looking for some detailed topic then check out the Main markers of the Topic below. 

Topic:

• High-Ranked Staff
• Staff Characteristics
• How to Acquire the highest number of the Best Soldiers

The Guide will cover both offline and online components and here are some basics you need to know about the gameplay.

• FOB's is essential to obtain new soldiers with S rank and above baseline stats which excludes without medals or other boosts. 
• You will never find S+ soldiers in the field, not even if you have over a million heroism and 4 FOB's. 
• FOB's is required to collect 1 of the 3 medals and is also the fastest way to acquire all 3.
• Staff levels don't actually matter that much to speed up FOB. The Reason being Snake or his custom avatar are the only ones allowed to use the bionic arm and the bandana / infinity bandana, and with all bionic arm upgrades he will be the fastest moving character in the game with higher health regen and reloading than the staff you acquired. 
• It is possible to research every item in the game though R&D by purely upgrading mother base and acquiring normal S or A ranked soldiers without bothering with any of the additional FOB features. 

Why do you need a High-Ranked Staff?
High-Ranked staff are important to achieve a level even above Big Boss and also play as a Woman. You can use the soldier helmet to absorb a fatal sniper shot to the head. This actually works and protects you from the headshots and some other minor buffs. Those who do not wish to participate in FOB's can simply ignore the online component. 

Online:
Higher ranked soldiers spot the invaders very fast and also defend your base with better eye sight players. You can reap all the benefits such as marking all the security devices on the first FOB you invade with S rank or higher in intel or support or medical. Also, a S++ Soldier in combat will be remarkably tougher than the Snake, though.

Offline:
A Combat Unit Soldier with Rank above A++ will take more damage before dying from lethal attacks than snake whereas non-lethal attacks, however, seem to operate the exact same way. A Combat Unit Soldier with a specific Skill such as Botanist which can acquire more herbs and quick draw can give you marginal benefits. A Soldier with higher rank from another field such as support or medical will allow you to Fulton faster along with marginal benefits.

Different Staff Characteristics

Fulton Extract:
The Most common query here, what really happens after you've Fulton extracted someone? After you've successfully Fulton the staff he directly goes into the brig or to the sickbay, now it totally depends on the Medical team on how fast they release them(Team -> Waiting room -> Dismiss). In the case of new members, they will show up as simply "not hired". 

Sickbay:
If injured / ill / PTSD, or when extracted from Fulton the Staff gets a bar indicating the time they have to spend in the sickbay. After the bar is down to zero the staff gets assigned. The Follow should be like a best possible team -> waiting room -> dismissed (not hired). Majorly the Fulton extracted staff from FOB's take a long time to actually become available to be assigned.

Direct Contract:
You will never lose your staff if you put them under Direct Contract, even if he is defending in FOB and get killed or extracted by the defender. It is very useful to keep a specific staff such as Miller in a team to boost morale, or keep staff in the waiting room, or a female soldiers and the staff you are deploying to boost medals within the combat team. The direct Contract is more useful with the highest ranked staff to avoid losing them from FOB infiltrations. 

Ability points:
The game does not provide us with a clear number next to each of the bars, but with some data mining the numbers can be found such as:

• E: 1-15
• D: 16-31
• C: 32-47
• B: 48-63
• A: 64-79
• A+: 80-109
• A++: 110-184
• S: 185-289
• S+: 290-447
• S++: 448+

It is very much possible to raise a staff's bar to exceed the upper limit of the display, but it is unclear if there is a hard cap to staff's ability points. The Team's total level is resolved by adding up all the Unit function levels of the staff which are assigned to it.

Skills:

Not-Story oriented Skills -

1. Diplomat (lessens effect of trouble makers)
2. Troublemaker (Harassment/Unsanitary/Violence) 
3. Medical specific (if their medical ability is the highest)
4. Counselor (hasten recovery of PTSD if assigned to medical)
5. Physician (hasten recovery of Illnesses if assigned to medical)
6. Surgeon (hasten recovery of injuries if assigned to medical)

R&D Specific Skills - 

• Various Gunsmiths (unlocks development if assigned to R&D)

Combat specific -

1. Quick Draw (Faster aiming)
2. Botanist (acquire more herbs)
3. Boaster (disguises rank in FOB)
4. Savage (does a higher damage punch)
5. Fortunate (fewer serious injuries)
6. Tough Guy (higher damage resistance or more health)
7. Quick Reload 
8. Rescuer (higher Fulton recovery rate, mostly useless with high medical team)
9. Athlete (faster sprinting)
10. Climber (faster crawling and climbing speed)
11. Gunman (more reflex time)

Cosmetics:
To obtain female soldiers, you need to rescue them in specific missions such as missions 14 and 23, and side-op prisoner extraction 2 and 6. They are captured as prisoners. Baring the unique characters of each player, the code name is randomly generated.

Medals:
There are 3 types of medals:

Service Cross -

• Any puppet soldier extracted from the field. 
• Any mother base member rescued during missions 17, 22, 27.
• Any soldiers extracted from FOB and subsequently recovered.

Distinguished Service Medal - Earn 9 Distinction points

• Completing missions while deployed (1 point)
• Complete dispatch Mission (2 points)
• Win an infiltration mission (3 points)
• Win an FOB defense (2 points)
• Win a practice FOB defense as part of security team (1 point)

Medal of Honor -

• Killing an infiltrator during an FOB defense mission(Each medal boosts all AP by 30).

Acquiring Staff

With a bit of data mining it seems that it's solely based on the total number of your mother base teams, for example:
TppMotherBaseManagement.RegisterStaffBaseRankRange{totalSectionLv=280,g=0,f=0,e=5,d=10,c=20,b=40,a=20,s=5,sp=0,spp=0}
This says, with an average department level of 40 (total 280), the spawn rate of soldiers with at least 1 S rank is 5%, A rank is 20%, B-rank is 40, C-rank is 20, D-rank is 10, E-rank is 5). Once you hit 280 total team level in mother base, s ranked soldiers should start appearing. This Does not mean that building more FOB's will spawn higher rated soldiers. Bases with 98 average team level are still with zero s+ and s++ rank spawns, and the rate for s ranked soldiers is still 30%.

Hint: The only way to receive s+ and s++ soldiers is through successful FOB infiltrations and defenses and finding volunteers.

One of the Best ways to Farm the S-Rank Soldier is HERE.

How to acquire the highest number of the best soldiers in the offline and online mode?

Offline Players:

• Fully develop mother base.
• Auto-assign and place the highest ranked soldiers under direct contract.
• Find the First Aid Manual in Bwala ya Masa and develop the Tactical equipment for D-Dog.
• Activate stealth camo once encountered the skulls, kill 3 of them and ignore the last one by running to code talker. 
• Go to mission 48 [EXTREME] CODE TALKER with stealth camo, a high damage primary (Brennan works fine), and a high magazine count stun secondary or primary (Riot SMG, Uragan, S1000 Air-shotty, non-lethal grenades and grenade launchers) to yield the high ranking soldiers.
• Trigger the cutscene and the game will spawn large amounts of puppets to the north of the mansion, the last remaining skull may cover the southern or northern approach, do not kill the skull yet as doing so will revert the soldiers back to non-puppet status. 
• Leave code talker alone as the puppet soldiers pose no harm to him. Go out and nonlethal every puppet with the camo on and command D-Dog to Fulton them for max efficiency.
• Kill the last skull if necessary and evacuate. 

Note: You'll not receive any of the soldiers until you evacuate and end the mission.

Online Players:

• Fully Upgrade your Mother Base and develop FOB's as much as possible.
• Go to relationships and support as many high platform count players(nuclear weapons preferable).
• Defend using the best-ranked soldiers without a medal of honor and always go lethal.
• Retaliation has a bonus to the number of volunteers and is basically twice as efficient as infiltrating. Saving a staff member also gives him the service medal.
• Infiltrate only when there is a volunteer bonus, for the rest just avoid.
• Always infiltrate with a staff with 2.00 multiplier and focus on stealing your way to the last platform. 
• Do whatever you want when Defending players while not even close to the objective.

Hope this guide was helpful with the FOB structure, excluding the all the background information that no one cares about.