The default gasket for aluminum heads is the Fel-Pro 1003. Don't use the shim gasket.
The 0.0035" variance is reasonable, considering that he may not want to spend the money to equalize rod lengths, etc. Like Cobalt said, make sure the tallest stack is at zero and the shortest is 0.0035" down in the hole.
Any used flat tappet cam and lifters are junk. You would have to re-use the very same lifter in the very same lifter bore, not in a different block. What do you think the chances are of 16 lifter bores on block #1 being bored exactly the same on the x and y axis and each one the same distance from the flywheel face of the block as 16 lifter bores on block #2?
Why would you spend 62 bucks for a Fosdick 5-quart oil pan? I doubt that it'll seal as well as a bone-stock production pan. If you want to make a difference, use a larger pan. 7-quart is a nice size for a street motor. Get the windage tray and crank scraper. Be very cautious about fitting the screen to the pan. You will need about 3/8" clearance. Less clearance can cause the pump to suck the bottom of the pan up against the screen and cut off oil supply to the pump. More clearance can cause the pump to run out of oil.