I do mean 'Millionaire' not multifamily, but wish that one existed!

This tells me two things: Obtaining a variance will be more difficult because there are already policy considerations in place intended to reduce density & (2) There is clearly an over supply of rental units in this area otherwise the overlay would not exist. 

This eliminates the requirement for a new down payment since you are refinancing the existing debt.Lenders typically require:A copy of the owner-financing agreement.Proof of on-time payments (6–12 months).What to Do:Find lenders that offer rate-and-term refinancing for owner-financed properties (portfolio lenders and DSCR lenders often do this).Maintain a clean payment history.” 

I am debating about the converting the existing old gutted building to either multifamily building (6 units each around 500 sqft small studio) or mix of 4 residential and 2 retail/restaurant conversion (the back side of the property has Big enough lot for outdoor dining or any other use cases.Any recommendations for use case of pure multifamily or mixed of multi family and retail?

Here in College Station, TX I'd say its no big deal just cross your T's dot your I's, and head on down to the local justice of the peace. 

Does anyone know if the mobile homes we purchased existed?  

Sadly the property no longer exists; it was at 22 Riverbend Drive sitting on the Swannanoa River, and like all nine houses sitting on the river, it was swept away and floated down the river.

Look for properties on main corridors or sites with existing structures (e.g., small houses or retail buildings) that can be torn down and redeveloped.Challenges in South Florida: Be mindful of market conditions and local regulations.

We are looking at investment properties in Brooklyn, and found one we liked and want to add an additional floor (two stories as of now, would go to three), but the zoning is M1-2, which is commercial.  90% of surround...

I can't compel competence that does not exist.