I can't answer which inspector to get, but for updating, I think I'd stick to accessories and make it look "spa like". Despite how convenient it probably is, I'd make the shelves/tv/boombox disappear somewhere. Hang some white fluffly towels. Swap out the plastic chair for a wooden bath stool. Also, there's bamboo bath mats and ones made of pebbles, I think that's the vibe to go for.

Most people would use it's presence as a negotiating tactic for money off because most wouldn't consider it a plus at all. They are huge energy hogs and the moisture issues they create also aren't great for a home. Unless you really really love it, and would buy it for the house if it lacked it, plan on ripping it out. An ad on craigslist and it's gone. No problem.

Ah! An area in which I have extensive experience, yay.

Ok, first order of business: how do we access the under surface of our tub, and what is underneath the tub?

Home inspectors don't inspect hot tubs. You will need someone who knows hot tubs.