When you will accept the offer, visa processing is next, in 2 days you can have your visa depending on their need and speed in processing.

Probationary is 3 - 6 months. If you pass, it is open ended contract. The length of stay entirely depends on both parties.

Medical will be X-ray and blood typing. You can make it on the medical for sure.. don't worry.

After getting an RP or residency permit, you can bring your family. Medical is good if -not better. I had a by-pass over a year and was done for free and was taking care very well pre and post hospitalization.

Family or single status should have been discussed by you during the interview. You can clear or discuss if you receive an offer letter.

If you are an Indian, you will gel at QP as it is populated by people of your race.

Cheers and welcome to Qatar.