63 Dodge Dart, now let me see;)

As for oil prime, I take the cover off and pack the oil pump with Vaseline petroleum jelly.

As for the valves, adjust cold about +.002 which won't hurt anything. After cam break-in and adjustments made you can idle it down and adjust the valves hot and running or by turning the engine and re-adjust the valves.
You certainly can do that. The slant 6 CAN even be primed, but it's kinda convoluted to do it. Before you install the timing chain, you can fill her with oil and put the bolt in the camshaft and spin it up with a 1/2" drill and cut off 3/8" extension with a 5/8" socket on the end. But we're a little late in the game for that.