In addition to do they allow subletting, you need to find out if it's a 55+ park, if the home conforms to rules about condition and appearance, etc.Once you have all that information and you decide that renting a home is possible and may be feasible, then you need to determine the rents that you can get over and above the lot rent.Then buying a mobile home is more like buying a car.

I'd say anyone in the country spouting off seller financing stuff would be something I'd be very suspicious of, most in RE are not finance types, they aren't underwriters, they usually view the deal as of today instead of the feasibility and likelihood of underwriting the future with a background of successful experience, like mine that had better loan performance than most portfolio loans at the banks.

Assuming it is feasible to acquire such a property, is this the correct approach to building up a solid cash-flow without overleveraging?

However, for most start-up investors, its much more feasible and easier to gather investors in a smaller area, preferably your local area and than launch outwards from there.

Do you think it's feasible to find a  property in decent condition for this price again (under $75/50K) as my first property didn't need a tremendous amount of work? 

I think I would probably advocate for that if it's feasible. 

This wouldn't be a feasible option for me, so in going the route of having the basement apartment designated as an ADU it seems in addition to the typical requirements (bedroom egress, independent egress, kitchen, bathroom, etc) I have also been told the building requirements for fire separation between units will be required (as per 2018IRC, R302.3).

It did not appear feasible that we were going to get anything at the price we were looking for in this seller's market. 

Welcome thoughts/advice on the feasibility and cost of doing such a conversion.  

Ordinarily I'd say that's a great suggestion, I'm currently in Mexico for work till Monday then fly to AZ to close on this property so a face to face meeting with an expert isn't feasible on my end to solve this current situation if I'm to keep the current closing date.