Well i have been friends with cabin crew for quite some time now so i do know all the info that you asked for.
As for the sim card well you need to get a photocopy of your passport or your QID and then take it to a Q-Tel certified outlet and fill up a form.
After that they give you a sim-card on the spot.
The locations that i can recollect right now are:
1. Family Food Center 1st floor( you will see it once you get out of the airport).

2. Q-TEL branches in LULU hypermarket, city center, landmark, Hyatt plaza.
Shouldn't be much of a problem cos its easily available.

Regarding the driving license well you need to get a letter from your company stating that you are an an employee there( proof of employment)
along with that you need to fill out a form to apply for a license. Attach 2 photographs and submit it at the local driving school here.
Once you do that they give you a date and and teach you for a set number of classes.
you are allowed to give a test during your classesif you feel you can clear it.
Rates vary from 1350 for 10 classes to 2000 for 40 classes.
Again you cant apply for a license until you have a valid RP(residence permit)which takes about 1 to 2 months.
as for your existing license you can get it verified by the local authorities and if thats approved then you don't need to go for classes.
You can directly apply for a test.
Will check upon it today and let you know.

You can rent a car and drive it if you have an international license.
No idea about rental rates.In case you need a cheap rental I know this guy who will give you a good rate.

I will check about the price for a Yaris and let you knw in some time.. Though cabin crew are not allowed to take loans from most banks out here.but HSBC does give vehicle loans as far as i know.

Hope this helps...
Lemme know if you need to know more...
Take care