All layers of paint need to come off to ensure the "bad" paint is totally gone. Back to bare metal is the only way to be sure.
I am not sure what you can do but you need to make sure the rust is not working away under that paint.
Maybe you are better off to sand the cracks and seal with aerosol...
I do not think that will work out as you are likely to breath to much of the oil fumes back in to the carb and therefore polluting the intake charge coming in to the cylinders. It will ventilate the crankcase but I believe you will consume oil and foul the spark plugs.
Doing what you are...
If you only want the crankshaft wouldn't it be easier to just by a Scat crank? or something like that.
That way you could buy one that would be internal balance.
There was a post on FBBO about Octane 6K LED headlights.
The poster was pretty happy with them and had a link to the Octane website.
I took a look and thought they looked good and a reasonable price.
I had a look at my car but you cannot really tell without pulling stuff apart.
The green one makes the most sense as it would protect/contain the wires all the way through the column mount/bracket.
So by the sounds of it it will still be externally balanced. That can make it tricky. It is hard to balls up an internal balance, but due to the counterweights being so far off centre with external balance a little too much or not enough can cause a problem.
I would contact the rebuilder and first confirm - is the engine internally balance or external balance.
If he has converted it to internal balance it will not need any counterweights.
You will be OK with those Edelbrock heads they are no worse than other named brands. I have come across faults on two other reputable brands - nothing that could not be fixed but a big NO to run out of the box.
The best part about all those heads is they use good quality components - valves ...
Yes they are a shop that specialises in the A833. They know the trans inside out.
I just typed brewers a833 and went straight to their website.
They sell a little install tool for that inner seal also if that helps.
In my experience most reproduction parts are expensive and disappointing when they don't fit right.
Some are complete junk.
Whatever you buy it will be a lottery.