I always put the lifters in dry (paste on bore and face) on startup they should all pump up within 10 seconds and no you should not be able to push the piston down by hand once they're full of oil unless of course they've sitting for a long time. If you can either the check valve is screwed and not seating or the piston or bore are scored. The valve springs will put a lot more force on the lifter than you can and over time the lifter may bleed down, this is normal, but should pump right back up after starting the engine.