I got it all put back together today. I looked closely at the seal surfaces before cleaning them up. It looks like the seal between the bottom of the intake manifold and the block (the "china walls") never sealed properly. There was no squish in the silicone there. So I did a better job of reassembly (I Hope) and, with luck, that'll be the end of that oil leak. I did get new head gaskets, new head bolts, new exhaust manifold gaskets, a new oil pressure sender, and a new dipstick tube (because I broke the old one off with the exhaust manifold).
I set the valve lash to where I could just rotate the pushrods with my fingers, plus one half turn. If there's a better way to do that, I'm all ears.
And it's not running because the timing is off, but I'm tired and I'll finish that another day. I need to refill the cooling system once it can idle and open the thermostat. Then it'll need an oil change as there is definitely coolant in the oil. I'm 3d printing a compression stroke whistle at this very moment to make getting the timing set properly a bit easier. I'm really bad at getting the timing set. It's trial and error, but mostly error. Maybe I'll have time to wrap it up tomorrow.