So a sponsor that's great for one investor will probably be terrible for another (and vice versa).I'm a conservative investor, so when I invest in multi-family I prefer sponsors that have at least one full real-estate cycle of experience, little to no money lost, low leverage, and high skin in the game.And there is an apartment operator that has multiple real estate cycles of experience (decades) with no money lost, low 65% less LTV, and high 10%+ skin in the game.

Not only after you purchase the property but what happens if you have an accepted offer on a property (and your deposit has become nonrefundable), and this 100% lender backs out before closing, you might need to find a normal HML that will require a down payment (skin in the game).Regarding the agent; I would not feel pressured to work with anyone.

In dressing millstones, the metal tools used, caused chips of metal to embed themselves under the dresser's skin.

I might look for another way to skin the cat on this one.  

Airbnb really gets under my skin.

The only other things that you'll need to consider if you go this route is that the primary rehab lender would not likely allow them to hold a lien on the property AND they may want that person to be on the borrowing entity since they in-fact are providing all/most of the "skin-in-the-game".

Lots of ways to skin the cat in this game and turn key is the easiest for most people to wrap their brain around.. just like you said you were having a hard time wrapping your brain around sub too... that's only because its a fraction of the market and generally done by folks more advanced in the business like a Mike  who do real estate more for a living than passive investing  a lot goes into doing a successful sub too..

I would want to structure it where the GC would have skin in the game, and we would split profits once its sold. 

Thats fine because they aren't putting any skin in the game.

Good luck.....and go 'skins!