That all sounds good. 

Do these numbers sound realistic?

Your experience in sales and market insight from your work and living in the Detroit area sound like valuable assets.

Remove and regrout, clean the mold, and replace broken tiles. 

Lennar is either 1 or 2 in size in the US DR Horton is the other.. they are production builder so yes quality is not their hallmark.. price is .. 2. wrapping the mortgage could certainly create an event of default with Lennars lending arm. there by trashing your credit. 3. if your buyer stops paying you have to keep paying and foreclose and hope they have not trashed the home when you get it back.. like all things creative finance wise sounds great on paper and is great if it all goes perfect but lots of things can fall apart if things do not go right.. so what is your fico score worth ?  

I am with @Paul Azad , this just sounds ripe for syndication. 

This is a relatively renovated house(all capex stuff replaced in 2019).

. :)Sounds great.

This will sound vapid, but one of the most important tools we each have is our ow minds and having positive self talk... 

However, to me it sounds like you are over simplifying this.