[Water Warrior 2]

Sounds like a pretty decent bike overall. You can do all of the above maintenance yourself while you completely go over the bike for loose fittings, nuts and bolts. Lube everything that moves. The bike is probably in need of a valve check too. I would leave that to a shop. It is usually a one hour job so won't break the bank.
The battery will likely need to be replaced at some point if original but that almost goes without saying on any used bike with little use.