I wrote up a species Highmonians. I believe it might require the Natural Flight and / or Tail species trait, though this would vary between members. These were (strongly) inspired by a race I used in old Fwurg for two NPC factions, and I'd be happy to rename them if people would prefer, but since they never saw much active use I figured it'd be fine

Name — Right now, it's not really possible for me to see the Highmonians as different from their namesakes of the old Fwurg; though that'll probably go away over time (I hope), so the name is fine with me, if somewhat strange to see in a different context.

Species Traits — Rules-wise you can have up to two species traits, so Natural Flight and Tail can be taken both. We have no rules for "some members have this, some members have that", but seeing how you are arguing for "some have both tail and natural flight, some only one, and some none" I see no problem. More relevant, species traits are only relevant if you plan on making a Jedi character.

If you do (plan on making a Jedi character) we might have to give it some thought, as Jedi get more training points if they start with less species traits -- and having the option to selective pick and choice from two traits for new Jedi characters is something others are not allowed to do right now.

I do not plan on making a Highmonian Jedi, so this should not become a factor.