Hi
First thing to do is get a base A1200 functioning without problem. If you start adding stuff from the getgo it will become problematic to identify issues. Just start with an unexpanded machine.
You need to identify the accelerator given that there maybe software issues.
As to the other stuff I only run classic so couldn't comment. But I am always nervious that users becaome over ambitious when they first return and finish up destroying another Amiga. Just go steady, record all your activities and ask here as you have done when in doubt. They are very special computers and need that extra special TLC.
Have fun.
