1. Those lovely heath and safety people don't allow you to run in boots when carrying weights but you can "fast walk" which just about equates to the same thing. At the end of week 4 there's the basic fitness test (BFT) which involves your flight of 8 people carrying a stretcher with weights and 2 pinepoles around the Knocker course with a time limit that equates to a "fast walk". Nobody failed it when I went through but it's not a pleasant experience.
If you really do have a medical condition then you can go to the med centre and get a "biff chit" that will get you out of having to do the test if it will cause lasting damage to your knees. The RAF yould rather have you fit to comlete the rest of the course than have you spending weeks and weeks on MASH flight recovering.
2. Time off! what do you think this is!
You'll get any holidays that the RAF as a whole get e.g. Christmas stand-down but that's only because the staff are on leave. Don't expect every weekend off either, you'll have community work to do and some compulsory sports matches to go and support. I managed to get a Friday off to go to my brother's wedding while I was at IOT and that was a real struggle to get.
3. When people from the RAF ranks go to IOT they continue to get the same pay as they did before until the pay they would receive as an officer catches up with it and then they go onto the officer pay scale. I can't see why transferring from the Army would be any different, best to go speak to someone in P2 or whatever they call themselves this week but I would expect you to stay at the same pay.
Enjoy the time at Cranditz and remember, it's just a game, play by their rules and get out asap!