Hi you ask some great questions but I think your putting the cart before the horse here and that will only pile on the stress and pressure.
The short answer is that BA can offer you everything you want but not necessarily at the speed in which you would want. TRI has a legal requirement of 1500hrs on multi pilot aircraft. You would be hard pressed to see it within 5 years and IMHO our trainers are generally very experienced. That said FPP guys are the top 2% in theory so why not. Seniority has little to do with it. It's down to you actually applying and then going through the interviews. If your suitable then you will be given the opportunity. Trainers work very hard in their training months and yes they get more money (not much more) but they loose out in duty pay so it's about even from what I have heard.
Rostering.......probably achievable if you put effort into your bidding and trading. If it's because of something at which you excel (sports) or you are undertaking further education the company are generally quite receptive to requests. Unless it's something like "I need every Saturday and Sunday off and I can't start before 10am on Mondays"
My suggestion is go for it. Come and join us. When it's not everything you want you can have a good old bitch about it. You'll fit right in then
