Keep in mind this is not a normal BD. It was all different, engine, trans, primary, forks, controls. All your normal thinking is a bit off. The advantage here is he could get a TH ASM Micro-Controller some Deutsche terminals, take the bodies apart and graft-in with the existing wires OR if he really wants, pull the entire harness and use the ASM harness completely. Axles, RIP, ESC are all designed for the controls we have. You do not need any of that. BUT are we sure the EHC is bad?
Another point in here, does the bike have any fuses other than the main breaker?