with regards to the rear exhaust hanger you could do what I did only cost about £3 if that, bought an exhaust clamp 55 mm I think found an old Mini bonnet stay in the shed for the cross bar & bit of welding job done
I had simalar problem with my battery a few weeks ago I had been working on the car with all doors & tailgate open which pulls a lot of power from the battery with 4 red marker lights on the doors 4 interior lights 2 footwell lights plus the tailgate light, my battery is only 2 years old I put it on charge over night & it's been fine since