I think 6 legs is pushing it but the rest of that is fine.
Oh when I said hexapedal I was refering to number of limbs not legs. 2 legs, 2 arms, and 2 wings, = 6
Though I'd suggest as a matter of practicality that aliens (or robots, depending on how good AI is in this universe) really ought to be able to speak 'common' natively or have a 'universal translator' on-hand (or not-so-universal). Wookie roars and R2D2 beeps might be okay in movies, but they're hard for PCs to deal with.
That won't be a problem seeing as my character will be half human. Raised in both cultures, multi linguial.
As to your questions:
Just curious, but why does she(?)
Yes
need to be a half breed? Unless Jemal has some indications otherwise, that would indeed seem to be entirely unlikely... unless it was deliberate? Say your other race is so strange in thought/custom, that they (or us, or both together) needed to build an organic bridge between them to communicate? A living translator equipped with the wiring of both species? Jemal did say that we had one extra-galatic species in the deck if we wanted to use it. That could be your parents. Of course, the reasons behind the "deliberate" might be more personnal (love comes to mind), though then you have to have had fairly powerful parents to have managed the interbreeding feat with ressources they commanded (doesn't have to be *your* parents though, nothing says the new breed has to be infertile (though probably only with itself without outside help, granted)).
My main reason for being a half breed is wanting to play the child of two worlds at home in neither type of character, and since we're going with the all humanoid possibly related because of [redacted], I thought I could get away with it. Star Trek does it all the time. If Jemal is interested in the half extra-galatic thing, I'll let him pm me. I don't wanna step on his toes, but I'm game if he's up for it.
By the by, if you're still going with your less gravity, higher pressure idea, you'll need some constant replenishing source injecting gas into the system (say accelerated degasing of the mantle or something, so heavy volcanic activity?), or dropping the gravity will automatically drop your air pressure as well...
You are presuming earth too much. Yes if we lessened the gravity of earth the atmo would leak away, but it would take millions of years... So what if it started much much higher, and this is where it's leaked to now? Or beyond that what I was thinking of is, Yes a heavier N₂, O₂ Ar, CO₂, would leak away with lighter gravity. But what about a N₂ Ar, O₂, CO₂ would be heavier without leaking away as quick simply because the Argon is more massive. Krypton would be even heavier but is less common in the universe.
Now if our atmo has too much CO₂ or we use some other greenhouse gas temperatures will climb, but you simply place it at a father orbit, or a cooler star, or lower albedo and achieve the same temperature. Always ways of making things work. Oxygen content would be the same but a lower over all percentage, and the atmo thicker so humans would have labored breathing.
I'm thinking a moon about mars diameter with with about 0.6 Mₑ orbiting HD 28185 b, with about 1.2 atmospheres that with maybe a 8 foot wingspan and hollow bones and some lightening of the body should allow flight if we keep weight below 80lbs.
If you're worried about it, the moon may be replinishing it's atmo with captured gassed that have leaked from HD 28185 b.