Dan,
Don't know the answers to your oil pump questions. But I can say that when you're putting oil back into the engine when you've got the pump & pan all back together pour a few of the 8 quarts it takes for a fill into the oil filter canister before you put the new filter in it.
That should help distribute the oil to places it's drained out of.
If you really were worried about a dry start, pull the relay or fuse for the fuel pump and crank the car over for 20-30 seconds. That in addition to pouring the oil down the filter and cam cover should have the oil mostly circulated through the system. Then you can re-install the relay or fuse you pulled out and start it up.
It will also help to use a 0w-X or a 5w-X weight oil to refill the engine with. The 0w oil will get circulated quicker than any other weight oil thereby minimizing the duration or possibility of a dry start (depending upon if you crank it over with no fuel or not).
I've been running Amsoil Signature Series 0W-30 in my M-Sport and it runs very well with that oil. I'd put that in the filter and cam cover and just start it up and not worry about cranking it without fuel if it was me.
Cosmos Black/Black 1995 540iA M-Sport
BMW Individual Exclusive Edition, 1 of 65 total, 9/25/95 Build