Cleanup turns to mess up. Need some help troubleshooting.

Well, if you re-read the posts, his early symptoms described carb flooding (gas coming out from under the carb base after the engine stops is a pretty distinct symptom of carb flooding, plus gas smell on the plugs), and the engine did fire and run OK for 20 seconds. So it makes sense to check the carb. The float being found stuck in the down position is consistent with those symptoms; it would never close the needle valve, allowing the carb to flood.

OP, when you attempt to re-start, you can just put a capful of gas right down the throat of the carb and NO fuel in the bowl, jump right in and crank, and see if it fires right up for a second or 2. This will let you know if the engine will fire at all, and will be a check on the ignition system with limited fuel available. Then let the fuel pump fill up the bowl as you re-crank and pump the gas pedal every few seconds to see if it will start and run as it should.

BTW, OP, in your first pix, the front exhaust manifold nuts looks to be on a very short stud. You ought to fix that sooner rather than later and get a thick brass washer under an inverted acorn nut like on the rearmost exhaust stud, so the front part of the exhaust manifold can move with heating/cooling. There is a very good article on this in the articles page of www.slantsix.org.