At the time of this posting, the wiki lists no class changes for animists, while in fact there are perhaps more than any other class. I'll list the ones I know; feel free to add.
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Petspam is capped to 14 FnFs in an area, whether yours or somebody else's. I'm not sure how big an "area" is. The 2018-12-13 patch was supposed to make non-petspam pets (not Animists' or theurgists' not count toward the limit; I have not personally tested this. You can always pop your controlled pet even if the area petspam cap has been reached.
FnFs cannot be placed too close to an enemy keep. This is calculated by where the caster is standing, not where the groundtarget is set, so you will be unable to stand inside the no-no radius and plant outside the radius, either. You can plant your controlled right next to the keep, no problem, or inside if the door is open.
FnFs draw aggro to the main pet, not to themselves. There are exceptions, the first obviously if you don't have a controlled pet out. The second is if the controlled pet is approximately 700+ units away from the FnF.
Bombers draw substantial aggro, whereas on other freeshards/live?, they draw almost no aggro. On other freeshards/live?, it takes appreciable bomber damage to pull a MOB off of a turret; on Phoenix, the required damage is trivial and usually the first bomber that lands.
FnF's aggro range is shorter than other freeshards/live?, about 700-800 units instead of 1000+. This also applies to the controlled in aggressive mode, but it has what appears to be a normal range for the "attack targeted" command.
Verdant vent shrooms have a casting range of 1000 units, equal to other 'shrooms. On other freeshards/live?, the range is 1500.
Shrooms in general and FnFs in particular had a number of HP / defense / damage tweaks and presumably no longer match other freeshards/live?, but by how much I wouldn't know.
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