Yeah, all the nuts/bolts can be replaced. I believe there are seven sets of nuts/bolts all together. Three on the front of skid plate and four on the rear. The front three are carriage bolts, the rear four are not.
I believe you can (don't wuote me, tho) disconnect the filler and vent tube at the filler neck and shift the tank to the right as you drop it down. That should let you get it out of there.
If you are replacing the skid plate and straps, the tank has to come all the way out, so you can take care of the lines/harness during that process I would think.