Hello Vissur,
First of all good luck. I am from Canada and I also went through the same procedure. Please see my answers below:

1.My face to face interview last around two hours. It will be a highly technical one(although they do not even do that kind of work), very detail in nature.You will see lots of them from the telephone interview.I was asked about lots of Java related questions, SW architecture related questions, different paradigms, life cycle bla bla. Also some behavioral questions. But you will be tested basically what ever they mentioned in the posting.

After the face to face interview, you will be seeing somebody at HR. Do not expect nothing much there, that person will check your diplomas, do a chit-chat. :)

2. NO. A BIG NO. Recent months, I have seen two persons were not hired after going through their face to face interview in Qatar. One of them is from AB,Canada.One person who joined from Scotland, was sent back after 20 days. You know, in the interview be nice, be relaxed, show your confidence, show a good attitude!!

3. I guess you were asked to provide with a date when you can come, they will send you the e-ticket accordingly. But do not expect anything in the month of September, as everybody is busy with Ramadan. I had my phone interview in October, came for the face to face interview in February and finally joined in May. But, if you do not get response from HR , convey that message to that person who took your interview. That person can speed up things. Please also do not push too much..:)

Wishing you the best. If you have any other question, feel free send me a personal message.

Cheers