THe lender is a credit union and it is a conventional low rate loan.

Many clients will find it hard to trust a younger person with this big of a decision. 

You look like the kind of person who is going somewhere.

I currently use Wells Fargo and it’s a pain in the butt to keep going there in person and setting up a security deposit account.

It would just need to be a situation where they have great contact with the person doing that managing of the project (I.e. have known the person for years, great reputation, person has experience in flipping etc.).

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

If you just find someone random person from those websites, you would be very lucky to find someone that understands REI.If you need a referral, happy to introduce you. 

When I go to get more work done, I use the person that was fairly priced and met my expectations that first time, I do not shop around again for the lowest deal.

Is there a point of contact person/business that handles all home investor concerns (general contractor, engineer, etc.)

Your name and credit would stay with the existing note, which you would keep paying on - ideally yourself with money you receive from the "buyer", because if they don't pay your credit is wrecked and your house is in foreclosure.If you search on here you'll see everyone and their brother looking to do Subto and it's a nightmare unless the buyer has the funds to pay the note off if/when the original lender figures out you don't occupy the property any more and are attempting to do what you want to do, since most loans are going to specify that performance.