We are turning to a renter nation, and big companies are still jumping on board in different times..

Very frugal lifestyle i.e.. bare minimum expenses, no children or pets, high deductible insurances, completely on board wife2.

Is it true that a developer has 77% of the owners on board to sell And that they only need another 3% to be able to buy out the building and take over the project of redeveloping?

I'll likely get a GC on board to help with that aspect or call around to different trade contractors to start building my own database.

Is the fiance on board?

its not a great house at a great price if noone is buying. and I will say that I have been part of neighborhoods changing for the better. however it's not something that can be easily done it would require moving into the neighborhood and an effort spanning years. and you can't do it alone you need other neighbors on board. it's not easy to gentrify the neighborhood it's not something you do it's something that happens. at least if you're close to the sheriff station it will discourage criminals and people with warrants outwhereare  the younger families buying homes and price your home under that.

Mgr to door knock to get the owner on board, then see if we can negotiate a reasonable payout with the county. 

There are hard money lenders who charge a lot more for their money, but just starting out you would need a really good deal for them to jump on board with you in all likelihood.By the way, you can’t finance a residential mortgage under a business name… so your newly minted business doesn’t help a lot there either.  

Get a great cleaner and handyperson onboard to handle anything that could crop up.

In a case like that, I'd say they weren't on board with the movement to start with.However, I have a PASSION for real estate and a burning desire to build an empire of properties and I would still plow my money into real estate even if other alternatives offered better returns in the near term.