In the store fixture business, we would clamp the drawer front in the approximate position, then shoot a couple pins through the back of the drawer into the front. Now you can pull the clamps, close the drawer, and adjust the reveals by tapping on the front without it letting go. When the bank of drawers is set, go back and screw them in permanently.

And drill hardware holes last?

Yes, hardware gets done last.

You will use whatever screws go with your hardware and are the appropriate length for the thickness of your fronts. If you want to countersink, you use a forsner bit on the drawer box and size the counter sink to normal screwheads.

The drawer fronts may be predrilled for installation on the predrilled boxes. Ikea does that. Ikea doesn't predrill for hardware. You do that after to lessen positioning mistakes and because of different hardware. Everything has to work as a whole.