Regarding the house allowance, if you got it with the total salary then its OK the company will not ask you how much you are paying since its included in the total salary.

If its paid as separate allowance, its suppose to be the same and the company should not ask you whether you pay more or less, as you may get house allowance of qrs.8000/- while you rent at qrs.5000/- as example.

But if the company told you to rent the house and they will pay the rent on behalf of you its also OK and they may hire the house and give it to you and they will pay the rent directly and in this case you will get only the basic salary.

For your taxes I thinks its better to have the house allowance separated than the basic salary so that you will pay less tax.

Good Luck & Nice to Meet You in Qatar