I would let the next buyer worry about any conversion on the garage as there are always permitting and township issues with upgrading an out-building to a living space. 

In order to do this, you would need to apply to build the 2nd story first, connected to the main home, then once the permit is finaled, you would apply to convert up to 500 square feet of that space into a JADU with a separate entrance.

He/She May also know a good real estate attorney  Have the prospective tenants asked for a TI?

For the first, try to get a sense of what various subs charge in your market per hour; for materials you have google and carrying costs include PITI, utilities, permits and fees and other standard costs of ownership. 

.: new surveys, higher permit fees, gas undergrounds).

An even greater amount are un-permitted multi-unit buildings that are comprised of series of shoddy additions. 

Go on the City website to see what "requires" a permit and what can be done without one.

I would be willing to work for free during my 3 weeks off with the prospect of working part time to full time.

Most agents spend their first few months in the business prospecting and just trying to get clients. 

I never cared for math in school,(NOW I CARE) but the more I dig in prospecting in 2020 going forward... the 'just go get a delinq tax/ect list' that every person tells every other person in real estate, is played out.