All the parts that you describe are all extras that are purchased separately from the tank. The old sending unit can be rebuilt to look and function like new. the "J" bolts should be ok, and you can purchase new straps, insulators, etc., or reuse the originals, if they were not damaged during removal. If the tank is in need of a cleaning, it can be boiled out at a radiator shop, and then you can evaluate the overall condition. These parts are not inexpensive. I just priced out a pair of J bolts and straps, and it was about $50 total. The sending unit was $85, and this isn't for a Cadillac!!!