To Aezeal.
What you don't see is completely your own problem.
That Jinn often turned invisible & changed their appearance is mentioned quite often. And this is what is said in the description of Glamour.
As for living in this world but being not of this world, it's unfortunately out of question.. Allah HAD made other worlds populated by angels according to some sources, but angels & Jinns are different beings - Shaitan sometimes appears to have common features with Jinn, but that's it. Jinn and especially "lesser" races of geniefolk are much closer to mortals than to angels - they may intermarry with humans and have children, including common with them, they die & aren't always especially long-lived, they are killed by normal weapons, etc...
I didn't met Jann in any sources I've seen except AD&D and there they aren't ethereal. As for being made of fire this is mentioned for Jinn in general, Perih & possibly angles (I'm not sure whether it's worth it to include Islamic angels which possibly wouldn't be different enough from those which Marignon, e.g., summons).
Sola I also didn't meet. Where did you find them? Name suggests something of probably Hellenistic/Neo-Platonist origins, though this is of course no reason to drop them entirely - if they are overpowered or aren't fit to the same patten as other genies, this will be reason enough.
What I would give to Efreets is larger combat form & smaller human-sized one, though I'm not currently clear about which advantages the latter should have. Both names are often used interchangably as I already mentioned, but it's possible to make 2 different subraces by making Efreets thugs & Marids mages..
I can use it as a good base. If you can't that's completely different problem - and not mine.
Any folklore has some discontinuity as it's created by many people during large periods of time, but for the same reason it mostly conforms to the common pattern. (I won't get to deeply into this here unless there is an interest). As I mentioned above, these patterns are relatively clear - but they differ somewhat between Arabian & Persian folklore (the latter, e.g., rarely describes Jinns as such, though it mentions them). And 1001 as such was written in Late Middle Ages, and in Egypt to boot! It contains Persian and even Indian influences - so I would prefer to use its patterns preferably in LA (I now think about sorcerers)...
#bonus means just it - & is mostly used for mount attacks, etc. While qeapon equipping shouldn't be a problem if the monster in question has only misc slots - you just can't equip weapons in them - excluding those which give #bonus themselves!
As for overpowered - I have currently no time for experiments with it in its various versions. Did you make any?