That "oven" is what I use to heat gears. If you leave it in there it will work fine.
I am not sure that red loctite on the cam bearing was a good idea. (I also wouldn't use it on the rod bolt/nuts.) Unless Onan specifies something like that (I'm doubting) they are to be installed dry. Hope you don't have to remove it. Installing it that way was a good idea. Cam bearing installation tools are expensive. I would have made the machinist who f***** it up install it.
That assembly lube is good stuff. As long as you have the oil pressure to clear it out. Don't use it on splash lube motors. It has to heat up to "melt" it out and let oil in. I shy away from it on all small engines. I use it on all other engines. Honestly, I'd recommend wiping it out and putting some gear on the journal.