Right, that’s what I’m saying. Not enough data to make hard claims, which is why I’m saying this statement is a bit of a stretch:

if a dolphin needs to they can breathe thru their mouths just fine.

As far as I can tell this has happened once ever. I’m not sure that qualifies as “just fine” when there’s more evidence that plugging a blowhole is very bad for the dolphin.

Do you have a link for that? Everything I’m finding says they can’t breathe through their mouth. There’s one scientific paper where they found a mouth breathing dolphin and said this has never been described in a scientific paper before. As far as I can tell there’s just this one dolphin who’s been seen doing it.

https://onlinelibrary.wiley.com/doi/abs/10.1111/mms.12349

Here’s a paper describing a dolphin that died due to blowhole obstruction:

https://meridian.allenpress.com/jwd/article/57/4/959/469580/Fatal-Blowhole-Obstruction-by-Eel-in-Common

To me it seems more like a one off case that a dolphin was able to mouth breathe, not that all of them can.

Horses still breathe through the same pharynx that food goes through. The question isn’t mouth vs nose breather it’s “what animals have separate pathways for food and air”, so a horse doesn’t qualify. It’s harder for a horse to inhale food because of the soft palate but it’s not impossible.

That air is still going through the same tube as the food though, regardless of nose or mouth breathing.