Higs can provide the most complete knowledge, I think he can even look up every AI rule.
To my knowledge, you can load a FG deck into the Trainer AI and it plays the exact same. There is no if this AI is this FG, do this branch of rules.
Now some of the rules were specifically coded for False Gods (See Hecate), along with some common combos of the past (See Ghostmare), The rest fall under a general set of rules, (See Perm Target Priorities), which might make you think that the AI plays different for certain FGs, but it's only because certain conditions are being met more often in those decks, regardless, the rules apply to the AI universally, regardless. So if you are level 80, and put a copy of Hecate's deck into the arena. The Arena will play it the exact same way. Many deck builders spend a lot of time figuring out the AI rules, in order to come up with decks to take advantage of gaps or highly repeatable steps. For example, Fractal, will target free cost creatures, and even for Decay that order does not put pests ahead of this, because of this, you can trick Decay to Fractal other cards.
The only variance to the rules is Paradox having 8 of 3 types of cards, but this is not an AI rule.