I wanted to give a final update on what I did for other peoples future help. Long story short welding to the bolt is the best way to remove them. I took it to my local welder and he said he had a "tool" for this. He welded a rod to it instead of a bolt and said he had a tool that grabbed the rod for extraction instead. He said he does it all the time and often the threads get ripped out with the bolt because its so corroded. In my case the threads were intact but I wasn't going to use them anyway because I already bought the oversize kit.
I already had a complete oversize kit so I was just going to use all three bolts it came with. I drilled out the two good holes with a drill gun and it seemed to go well. BUT when I threaded in the bolt it was off by a hair. I dont know if there is any real way to do a better job of this. It works, it just bumps the side of the port before pushing past. I didn't trust the original threads, the aluminum was SO soft and quite corroded. If you can get your hands on the original size bolts I would actually recommend just using those original threads because when I went and tested the ports you can tell the bolt didn't seat that well. One of them wouldn't turn off all the way and the adjust-ability was pretty poor. The only way to get a perfect fit is with original threads.
And as far as the one I drilled out and repaired, that was a long journey. First I had a machine shop drill a large hole as well as they could and it looked great but it ended up being off by small bit too. I was going to use a thread insert but when I saw it was off I just had it welded shut. Before I welded it shut how ever I made marks so I knew exactly where the port was. When I got it back from the welder I made a mark with a punch and drilled the hole with a drill gun. The hole ended up being spot on but a just a millimeter crooked. It ended up working because I enlarged the shoulder on the port so the pin would pop in. The welding idea was great, definitely way better than an insert. Plus I can re-weld it if I mess it up.
I was about to install the pipe and then I decided to test it. Good thing I did because none of the ports were working well. One was clogged up and the others were spraying a bit too much. ALSO the threads were leaking water pretty bad... That I did not expect, so I put thread tape on them and it only stopped leaking when I tightened the retaining nut. Plus I found one of the ports wouldn't shut off no matter what, almost but not all the way. That's good to know.