You will still have an electric bill even if tenants pay their own unit.

Start with house hacking, invest in credit and education, and leverage electrical skills.

@Ori Skloot can you give more details on the electrical and plumbing work you did?

Utility Costs (Water, Gas, Electricity):- Paid monthly by the tenant unless included in rent.

if the electrical needs to be updated, that is OK as long as that is factored into the numbers, and as long as you have someone competent to do it.  

But larger repair items such as appliances and mechanical, plumbing, electrical, roof windows doors etc should still fall under the landlord's responsibility.

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?

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

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.