So... if I were to advise a friend, I'd tell them, sure, if you really wanna buy, this platform is fine, just like Roofstock is fine, if you really don't have a team built out and trust built in to find better deals & opportunities.

Glad you asked my friend.  

I read a forum post on a personal finance blog about a user using YNAB and Credit Karma together to problem solve. 

That's why I think investors are not your friend, you want retail buyers.Have you talked to the neighbors on all sides of you? 

If you find a sublet-friendly co-op and it requires an "All-Cash buyer", there could be a good reason.The points you mentioned regarding co-ops are valid but do not apply to all co-op boards across this market.

These can sometimes offer better cash flow, especially if you’re in a family-friendly area with unique features like extra square footage, an ADU, or flexible layouts.

I doubt that owner-occupiers would be the early users. 

Check out FilePlace, where user-created forms are available for free.

I am creating an llc with a couple friends as we go into this new endeavor.

It would be a huge mistake to jump into a strategy without understanding how to deal with problems that may very well arise, more especially when the property is in tenant-friendly states.