Page 81 of B52E there is a page which is speaking of salaries.

It is said that diplomat, officer and soldiers and all minbari have average lifestyle provided by their parent organisation (and the Federation for Minbari). does the lifestyle, includes somewhere to live, like a room in B5 or whatever ? or does the player also have to pay for it ?

same questions if you pay yourself your lifestyle.
If the average lifestyle is paid for that will be enough money for all the stuff that the average lifestyle includes - accomodation, food, the occasional real meal, and a hobby or two.