Yikes, condolences. The servo part is weird, problems with the esc is understandable since it’s supplying the power, even though I would of guessed the BEC would blow before melting wires. I could see possible problems with the receiver power connections too.

But the servo, would of thought it would basically act like it was not powered/under powered, that’s weird. Unless damage to the receiver dumped voltage to the signal wire?

Suggest being careful with the receiver, try to check the voltages on it before connecting a servo. Perhaps the same with the ESC without the receiver, take it one step at a time. Maybe start the receiver checks with the AA receiver battery instead of the ESC for power, and feel for heat as you go. Good luck.