Paid holiday plane tickets

You have the right to ask for a plane ticket (sometimes even multiple), insurance, etc. You can even renegotiate your housing allowance and salary if you want to, your housing allowance seems pretty low actually I would ask for 400-500 BHD if that's for housing plus transportation, also I see that you are Spanish national so you definitely have a leverage here. Contracts are fair game as long as you are not asking for something too ridiculous. Don't fall into this trap and make sure you get everything in writing from your employer. Also what is your current job? this can help to have a better idea of what you do and if you are being tricked by your employer.