However, that depends on the time/energy/skills he puts into it.I

You would want to check local zoning to make sure you could build more than one as a lot goes into that beyond just being close to plumbing, electric, and gas.When you mention "a lot goes into that beyond just being close to plumbing, electric, and gas," what are the top things people tend to overlook when preparing to build ADUs?

.- Spend your time and energy on getting deals, not on imitating podcast hosts.Good luck.

Take this opportunity to upgrade your plumbing and electrical if needed. 

Yes, there are added costs to this, but what is your time and energy worth?

Optimally, the lawyer or the firm should be familiar with public infrastructure that developers are typically asked to pay for, such as road widening, turning lanes, new roads, sanitary sewer extensions, new water and electric extensions, fire hydrants, etc.

It is difficult to recapture the electrical savings from the tenants. 

If the landlord was aware of his past, yet rented to him anyway - any lawyer worth their salt would make a nexus between those two pieces of information and create a liability claim.In addition to the extreme negative press you would get, it also takes time, money and energy to defend a lawsuit you will eventually win.

Have a salon with a water heater that was installed around three months ago, and the tenant has complained that it's having issues heating the water; I suspect it may be an electrical issue with the system. 

I hired a GC to manage the build out, but there has been no consensus on who is responsible for the utility payments (Water and Energy).