I know macro economics is important so anyone can search the internet and come up with their own theories on the subject or a more favorable example and that's great, but this is just my personal experience.

GPs do not like to put material portions of their net worth into deals.

You likely won't find your answer on the internet, FB marketplace is a good start, but I found all my help up there through referrals and picking up the phone. 

It's better than what you'll get from most attorneys and what you'll find on the internet.

No, material costs sit nearly identical.

Question 1: Does $4698 for materials and labor to prepare my house for a hot tub seem in line?

I was able to negotiate a package that included the land, some of the materials, and the permits to build it.

When you have a big cost segregation depreciation plus your big startup expenses such as furniture and supplies, and you then have a big tax deduction against your big W-2 income because your passive losses are no longer limited with your big material participation, it increases your audit risk a ton.

Some mentees will act as a bloodhound for the mentor, knocking on doors, driving for dollars, scouring the internet, making cold calls, or performing other services that help the mentor find new deals.

The first way is build a team large enough to do it all in house, now you have a crew lead who can go estimate time and materials to get jobs done.