I have a BS and MS in Engineering and I design Class III medical devices for a living.   

Financial, medical etc.

When I search there are some commercial NNN properties which are around or over $1MM with corporate guaranteed leases for atleast 10 years and goes up to 20 years (like Fast food Restaurant chains, Banks, medical offices etc).

Tertiary goal is to learn enough and build enough so that when I do retire from the fire department I can take my knowledge and skills with me to my new location - most likely a beach somewhere in the Carolinas - and be able to invest locally in beach rentals. 

LOL.. figured with my Tesla I have no gas.. and I get bored sometimes so I though maybe I give folks a ride around and socialize a little. .. but then when I read the fine print that I had to accept dogs.. that was a no go in Oregon they would be wet and smelly and muddy.. so my lyft career never lyfted off LOL.. on a side note.. one gig I like that is real estate related for those looking for extra money is that of a transaction coordinator realtors really rely on those folks and you don't have to drive anywhere  computer great scanner and some skills.. my wife pays her 400.00 a file.. and she closed over 30 files last year.. so that's just one realtor and her coordinator has many realtors I bet she makes well over 100k a year from her home.. ( now she is very good I want to emphasize that ) 

But if you've got time and/or other skills to devote, a less-than-perfect credit score can be worked around. 

Typically, I would base the profit distribution on the initial capital contribution, but I am not sure if that is equitable in this situation as his skills will likely be needed more often than my skills as an attorney.

If you're trust worthy, skilled, business savvy, then go buy yourself the project, work on it, and own it yourself. 

It's just that I'm anticipating a "better" tax situation next year - that is, for personal medical reasons in my family, I'm anticipating a lower level of income next year.

You're also going to need an extremely skilled transporter.