Did you find out what the problem was? I’m having the same issue.

Not sure what the other question was that you are referring to, but regarding your expressed concerns here -- the battery light will only come on when the charging system is not working properly - whether due to a wiring or alternator problem, or if the drive belt has some how come off. Testing will need to be performed to find out what is going on. As far as the transmission not shifting into reverse gear, this may be related to low system voltage, but could also be a separate concern altogether requiring troubleshooting.