You state that your truck is a 1500 , ie 1/2 ton. The reason that the cummins was never offered in 1500's is they are too heavy for that pickup. Note that 2500's & 3500's have larger frames, heavier suspensions and bigger axles than 1500's. Not saying it can't be done, just that in my oopinion your truck ain't bulit stout enough for this swap.

As for your other questions I'll have to let somebody else address that.