depending on your lease, the original tenant may be harboring the other tenant and be violating, I may consider discussing with the tenant (assuming the lease specifies who can live there for how long) that they are in violation of the lease, and you can remidy 2 ways, volunatilly terminate the lease and resign a new one with the additional tenant, or you can go down the eviction route. 

In addition to spreadsheets, I was curious if anyone uses a checklist when analyzing properties; a series of questions, reminders, and information to acquire as a guide you use? 

They are definitely hands off, 1031 exchange eligible, and have been a wonderful planning tool for a lot of folks...including those that still own/manage real estate in addition to their DSTs.  

From my previous learnings, my initial strategy is to invest in a duplex and "house hack" while gaining more experience to invest in additional properties. 

Additionally, my parents are giving me the option to receive a lump sum payment to go toward possible rental property purchases.

The only benefit to a lease option, really, is that you can charge them rent plus additional for the principal balance, force them to pay the taxes, and take care of the property.

He receives the BAH in addition to his normal pay.

Yes, i am looking for long term hold and rents, i dont have enough experience in rehabbing to do a flip yet, due to my physical limitations from my military days, i am striding to increase my passive income to a point i can comfortably live the rest of my life on.In regards to the %, i have no clue, i have gotten multiple comments to just go by the percentages.... with no additional details.

Additionally if there is anything amiss with CAM payback by tenants or questionable then a seller hold back for CAM usually 6 months is held for buyer.

In RI it's attorneys who handle the escrow/closing, rather than title companies.Usually in Rhode Island, if you're using an agent and the standard RIAR (RI Association of Realtors) purchase and sale forms, you wouldn't engage an attorney until your offer is accepted (which in RI is the same as getting a signed P&S back), unless you or the seller is putting something out of the ordinary in the P&S (usually in the additional provisions on the last page but there are a few other places extra language can be added).In that case you might want to bring in your attorney to double check the language you or (especially) the seller are proposing, just so you understand what you'd be committing to.I'm not sure what your connection is to Rhode Island but since your profile says you're in Maryland there are probably some differences between the two states when it comes to real estate.