What is the best way for a DIY'er to work with contractors/inspectors?
You might find such a person, but it'll be tough. I suspect you'll spend a lot of time on the phone, reading your 4 points out, before you get someone that's willing. My guess is that you'll end up finding an older, semi-retired handyman type.

Concerns/roadblocks include (but aren't limited to) the fact that you're asking the trade to take some measure of responsibility for your work. (I know you said 'inspect', but sometimes things get buried/missed/fail later, and that would make a trade nervous.) The initial "brain dump" sounds good, but I sometimes find that I can only make choices once I'm elbow deep in a job. That, and you'd need someone that communicates well. The last thing that springs to mind is about specialty tools: if I've invested a grand in door hanging stuff, it's easier/faster/more cost efficient for me to just hang the door than to instruct you on how to work through it with non-specialty tools. (Though maybe you're heavily tooled up and this wouldn't be so much of an issue...)

Anyway, I do wish you luck. I think this approach can work for some jobs, and won't be as applicable for others.