Arabic is not so important to do all those things The advantage is in terms of money saved. dealing direct with Car rental agencies is very easy and straight forward.
as for furnished house dealing direct with the landlord is far much better then going through the real estate agencies.
By utilities i presume u mean Electricity & Water u can do a deposit of Qr. 2000/- n have it in your name by going to the KHARAMA OFFICE.
Most of the furnished hse have tel. Tel payment u can do on line.