Why is it, that even in scenes taking place outside the Cabana, all of the animals have on only underwear? The theme song implies that it's supposed to be that way only at the Cabana ("At the Banana Cabana, your pants won't be missed").
Maybe all of the employees just happen to be fond of... not wearing pants, and it has nothing to do with rather they're at the Cabana or not?
I figure it's best not to look too deep into this given the fairly basic concept is right there in the title and there's no real need to divert from it, Rule of Funny being the only thing the series runs upon. Any theories as to why within their universe no animal is actually clothed is pretty good content for WMG.
Theme song writer wasn't paying attention. Simple.
Why is it that Bunny doesn't wear a bra?
Same reason Dot or Minnie Mouse doesn't. She's not "developed" enough to have one.
Why is Batty apparently wearing panties?
I guess Batty is a girl. Bunny doesn't wear a bra but has panties on so I think it applies to Batty.
Why are all the animals shown with hair/fur even those who logically shouldn't have any?