With Greenleaf in your possession, it’s time to turn your attention to Fontaine. The most powerful of the first three fiefdoms, Fontaine is focused on water-type Pokemon. This means that your recent takeover of Greenleaf can be a great boon. However, there are a couple of minor issues.
If you prepared yourself well for taking Greenleaf, you have a number of fire Pokemon- who won’t do well at all in Fontaine, for reasons even beyond the entirely-water-based enemy forces. Additionally, two of the Warriors you can gain for your army when you take Greenleaf use Sewaddle, which despite having a beneficial grass typing, uses a bug-type attack, making it less than optimally effective at handling the forces in Fontaine. This means that you basically have two choices to make. The first is simpler- do you go into Fontaine immediately, or do you seek more trainers in Greenleaf?
A lot of what you’ll see in Greenleaf right now in terms of trainers is people with Cottonee. While not terrible by any means, Cottonee are relatively fragile and not terribly strong on the offense. This may not matter, though- with Fontaine full of water Pokemon, Cottonee’s Mega Drain attack presents it a huge advantage. Unfortunately, you also have to be rather lucky to even get that- more likely there are not going to be any trainers available in Greenleaf at all. On the other hand, you could get especially lucky and spot a trainer with a Carnivine- the floating Pokemon’s ability to ignore terrain and its Vine Whip attack make it a very useful team member, should you get the chance to snag a Warrior with one before heading towards Fontaine.
While you could just spend some time training your forces, your overall power is probably plenty to handle Fontaine, so spending more than one or two ‘months’ preparing isn’t really in your best interest here. Besides, you haven’t gained access to the ability to Link new Pokemon with your Warriors yet, and without that you’ve got virtually no ‘perfect matches’- in fact, a number of the Warriors you have are toting around Pokemon with whom they have only passable sixty to seventy percent Link maximums, or even something as low as fifty-two or fifty-four percent. Although this isn’t even really a noticeable problem at this point, you’re going to want something much better available in the late game, and time saved is time saved, after all.
It is possible to train your Sewaddle until they evolve into Swadloon and gain the long-ranged and rather strong Razor Leaf attack, but the Link rating required for this is very high, and they will long since have become strong enough to win the entire fight without support- not to mention that it will take many, many battles for them to approach this level of power. This overall constitutes a waste of time since you can easily take Fontaine before then, and even so, it’s unlikely any of your Warriors with Sewaddle will want to stay with Sewaddle once you gain the ability to Link them to new partners. This renders the ‘third option’ for this decision pretty much moot.