The American system is designed for choice, FREE choice. 

I reached out to an individual selling a home for 45k, cash only.

You may already know this (you should know this), the JADU requires owner occupancy on the property to be rented as an individual unit.  

My initial question is… Is it good or bad to have individual septic for each mobile vs one big central unit??

If it's just a laundry room, it's really tenant's choice.

You have lots of other choices in the free and paid space. 

This City required individual lot grading plans, signed & sealed by an engineer, for each building permit.

Hi Geetha,The NCREIA meetups in Raleigh and Charlotte are a fantastic choice—they attract real estate operators at every level, so you're definitely in the right place to build connections!

However, if you have conveyed the information to them via some type of written from.. that is a good option to leave it to them on what their choice is and move.

As someone who moved to Waco from Miami just because my wife got a senior position in Magnolia, I've met many families and individuals who have come to Waco from LA, NYC, Seattle, etc. just to work at Magnolia, SpaceX, Baylor, and some big churches in town, such as Antioch.