your lifters should be fine... Depends on how many miles you have on them... There are plenty of people running 170k+ on stock lifters. But then again with this added lift and spring pressure it couldn't hurt anything..
I also think you will be good, but I would def. check the p/v clearance on a cam swap to be sure. As for the lifters, I still run my stockers...and my stock pushrods.
So hows Hawaii treating you man?
Good Luck
I know people who have the factory lifters that have been in several motors, Probably ok to leave them, I did in my last combination, but a new set of Ford Motorsport hydrolic roller lifters would hurt either. My friend did have a couple go bad.