Board Game Arena

So right now, the game lets you select the upgraded Animals card at strength 5 even when you don't have the money or enclosures to place an animal. This is somewhat understandable because of the reputation increase, but what happens if, for example, a player chooses that action in this situation, gets to a reputation point that lets them get a card, and chooses to draw from the deck? If the player still has no valid animals to play, the game is now deadlocked.
How much should be allowed in this situation? Should it stop you from drawing from the deck unless you already have a valid animal play?

The rules as written, in my opinion, suggest you should be able to take the upgraded animals action at 5 without playing any animals.

The animals action says play "up to" the stated number of animals. The reason you normally can't play 0 is because the rules for taking actions states you "can't do nothing for your turn" and uses "playing 0 animals" as an example. But with upgraded animals 5, I would say gaining a reputation is "doing something", so in my opinion you should be able to play 0 animals if you are gaining a reputation, since 0 is up to 2.

On the other hand, the designer has stated on bgg forums that his intention is that you shouldn't be able to play the animals card without actually playing any animals, as in not just for the reputation point.

BGA will allow you to take upgraded animals at 5 just for the reputation - or at least I believe it will, someone made a thread about this on bgg a few days ago. So current implementation, if you gain the rep and fail to have an animal, I believe you would just pass playing no animals.

In a world where designer intent is respected and you aren't allowed to play animals for no animals, I imagine you simply wouldn't be allowed to take an animal off the top - or you rewind the turn like the rules for venom tokens states, so you simply get to look at the top card of the deck.

The current BGA implementation does not allow you to pass without playing at least one animal, so that much is at least correct.

You cant play the action card just to get the reputation point.
BGA is letting you select the action card and get the reputation point, but you wont be able to pass the play animal part. The only reason we are letting the player start an invalid move is always the same : we cant detect generally what is valid or invalid. Gaining a reputation point could start a chain of combo that finally make the "play animal" part valid. Easy example : you have no playable card in hand, not enough money to play one card from display, you take the 1 rep, you get 1 card from reputation range and now you can afford it because you dont have to pay the folder cost.
You can imagine more intricated scenarios so in general the adaptation will just let you do any action even if you cant finish it if there might be some way to make it doable (in a very loose way, we cant compute all possible paths and it will give too much informations if we would highlight a doable action that the player hasnt realized a chain a combo could make it doable), as long as you can always undo. That is, when you are on the verge on doing an undoable action, we check that you have no pending mandatory not-doable action (which might also be too restricted sometimes, for instance when you can sell cards for money to pay venom).