So this is a tough situation to help with. It's tough b/c as an experienced mechanic I've gotten used to seeing and thinking of problems in ways that help diagnose the what's wrong. Your description may be right but it doesn't match up well with what I'm used to seeing.

Sucks that you had a fire. Hopefully it didn't result in other damage! I think a fuel pressure test might be a good idea. Low fuel pressure can cause hard star, no start, and backfire. I'm not sure what else to recommend at this point.