Animal Shapes

Recently, a player of mine started wanting to use Animal Shapes on the classic Rat Bag. After using "Animal Friendship" every day for months on a friendly group of hamsters, he'd like to use Animal Shapes to transform them into hippos for a fight. Granted, the hamsters actually become friends, does he still have to persuade them to fight? After all, they're animals and aren't dominated by the druid. Given that even as elephants, they retain animal intelligence, is it plausible that they'd hurl themselves into walls of fire or dragons? Also, even granting that (he's really put some effort into it), what are the ways to counter the spell? Massive damage (meteor shower), anilife shells? Flying? It doesn't require concentration, but I was wondering how the beasts would behave if the aforementioned druid ended up on an alternate plane. Or was incapacitated.

Animal Shapes does not give the caster any control over the targets, nor does it change their mental stats or behaviors. They would still have the intelligence and mindset of hamsters. I would say hamsters are probably smart enough to avoid a wall of fire or a dragon, since most animals are instinctively afraid of both fire and creatures much larger than them.

The caster's ability to convince them to do stuff for him is exactly the same as it was before casting that spell on them. If Animal Friendship is cast on them, then they're Charmed, but that also doesn't provide any actual control over the target. It would provide advantage on any ability check made to convince them to do something, though.

As for countering this, the most obvious method would be Dispel Magic, which can instantly eliminate the effects of both spells at once (though only one one hamster/hippo at a time). The Druid being on an alternate plane or Incapacitated wouldn't have any effect on either spell.