Any way to capitalize on this garage outside of just attracting higher rents once I move out and/or higher sales price if I decide to sell?

There is a much better alternative!

Alternatively, he could simply pay down the mortgage by $1k on the 15th. 

I’ve included a photo for reference of the kitchen which is the main attraction of the Mass home.Now I am looking to pursue REI long-term and am looking for tips on how those more experienced in the field have operationalized and scaled the property selection process.Our thinking for this first official investment is to either acquire a duplex/triplex and add our touch or acquire a single family where an ADU can be added.

., etc. for example finding cash flowing investment properties which meet your ROI goal of 9% is NOT HARD heck almost every state (and likely every state) has a market which will achieve that but what does 9% mean without a dollar value if 9% is = to $200 or more okay that’s okay but if 9% means $25/mo. or alternatively if 50% ROI means $25/mo. doesn’t really matter much since although labor differs from area to area it doesn’t differ that much and also doesn’t really leave much room for error — so your minimum accepted ROI should also be couple within a minimum accepted $$ value (cash flow) and other minimums as well (i.e. min. equity, property types, property classes, etc.)Lastly as I mentioned achieving a 9% ROI is not hard and is achievable in every state; the HARDER part is to 1) achieve that AND 2) achieve 10-20% min.equity on the buy in or ARV AND 3) meeting your min. $ value AND 4) buying in a good/stable neighborhood/market AND 5) buying with some type of upside AND 6) etc. etc. etc. —- Again I’m not saying you have to do these things; it all depends what type of investor you are and what you are looking for however it is important to understand that if you shift the responsibility of either identifying the invest property or managing or any other aspect there WILL be a trade off — in this case the turnkey company has delivered on your goal of 8-9% ROI (projected... so TBC) and in return you have traded some of the other benefits of investing in RE for the convenience of not having to do much more than to look over the properties they have sent you and funding it from the comfort of your home, office, etc. ... again if this is the goal then you are on point but if the goal is to also partake in ALL of the other benefits of RE then you should understand that and not be surprised that it’s not a ‘stellar’ investment that checks all the boxes.

Low down payment (3.5%) is attractive, but comes with mortgage insurance and might not offer the best rates.

Or alternatively any of the following that would have a similar outcome.

@Nadia Jones Starting and running a fund is a separate business because it's something that you need to actively market for and regularly work on attracting capital to invest in. 

The older you get the less attractive appreciation is unless the goal is to leave some kind of legacy. 

Debt is attractive to most people because they don't have the funds to do a project and instead of saving for years this is faster and easier but things go wrong and if you don't have reserves you can quickly find yourself in trouble.