I was just wondering, what Gods do they worship in Akavir?

Probably some Aedra like in Tamriel. I'd imagine the gods would also be Akaviri versions of the gods we have in Tamriel as well. And maybe the Daedric Princes has some kind of presence there too? Remember though that this is just speculation. No one really knows what religion beliefs they have.

The tiger people Ka Po Tun worship their emperor, Tosh Raka, the Tiger-Dragon. He may have somehow wormed his way into the Time Dragon Oversoul, like the High King of Alinor, or could simply be a Tiger person who underwent dracochrysalis.

Almost definitely Lorkhan.

There's some vampiric-snake men there.. so we get Molag Bal and Lorkhan imagery there..

Boethiah.

Judging by "http://www.imperial-library.info/content/tsaesci-creation-myth-and-we-ate-it-become-it", themselves... really, what else does "Tsaescence" mean?

I like to think that the Tsaesci "pantheon" consists of forms too shifting and protean to compare to our already ambiguous godmass of Aedra and Daedra. As for their demons or "acceptable blasphemies"... perhaps unswallowable poems, or immutable theorems or platonic forms?

Your guess is as good as mine for the rest of them, although I hypothesise that the Kamal mythos is a perfect inversion of everything the Nords hold dear.

Do we know of any Elven-like people of Akavir or are they mostly man/beast people?

Since they have the Dragon connection and are opposed to serpents, I`d say the Ka Po Tun qualify, especially when one considers that the Khajiit and Bosmer imply that beast-traits are a natural result of elven subgradience.