some progress and some decisions.
That silver tube is a capacitor which works like the one in your distributor to enhance the lifetime of the points, though of course not forever.
If you go with an electronic circuit board you won’t need that.
You did what I was going to suggest, propane torch on the sheared screws, taking advantage of the thermal expansion of AL vs FE.
Your one-way valve is different that mine, which is just a flat disc.
The main trick with rebuilding these is to screw in the diaphragm shaft the right amount, so the points throw over but don’t get stuck.
There is also a breather hole in the iron body which should point down so in case any fuel gets in there it will drain out.