So, maybe this question was answered already, but I'm pretty sure it wasn't. I will post it here for a moment, just in case - if it really wasn't, tell me, and I will move it to "submit questions" forum
so, on to the question...
I always thought - which level are Djinn like Shubit, Queezle, Faquarl and Jabor?
The book said Bart is level 4, but it never said anything about other Djinn (or if it did, could you please remind me...?)

No, I don't think they said- just that Faquarl was a bit above Bart in Power and skill.

Ok , I will move the question to Q forum then...

It can take some time before Stroud answers you- he's quite busy lately.

Well, with "Whispering Skull" premiere still probably going on in some countries, I expect him to be busy :D