I'm not really sure how to answer you first question since i couldnt compare it to other servers but i would say its busy not anywhere near being dead but not as busy as balmung or gilga.

Pf usually is full with Pony/Bird Farms, FCs recruiting, Raid Groups looking for members, Weekly Savage Kills, Savage/Primal Kill sales. Stuff like that.

Community wise there are alot of friendly people on phoenix but also alot of trolls and the undercutting is very bad.

Well you will find some other languages than just english on phoenix but its not as bad as shiva or moogle. Actually the english speaking population is rather high here.

Housing situation : no empty wards

I would recommend you making a alt first and check it out yourself. But make sure you create that alt late night or early morning