When you say "rechecking a bag" do you mean that these are separate flights on separate tickets? If that is the case, I don't think you'll make it. You'll have to get off the plane, go through immigration, collect your bag, go landside to change terminal, drop your bag off again, go through security. That's a lot in 90 mins, really only 50 as boarding will probably start 40 mins before departure.
I'd say your chances of making it with checked baggage, on separate tickets, are close to zero - the only chance you have of making it is to travel without checked baggage. With carry-on baggage 1.5 hours is do-able as you would be able to transfer airside (T1 and T2 aren't really separate terminals - they are separate check-in areas, but airside it's all one terminal)Edited: 5:08 pm, June 09, 2018
#3, you won't have to re-clear security.
If you are bussed to the terminal make sure you take the escalator upstairs before you reach baggage reclaim. If you end up in baggage reclaim by mistake then you will have to re-clear security as you will have left the sterile area. It's very easy to miss that escalator (I nearly missed it the one time I transferred at HAM)
If you disembark via an airbridge you will disembark straight into the departure area and all you need to do is walk to your gate.