The only way I see a low or no-money-down scenario being viable is if you have a lender willing to lend based on the Loan-to-Value (LTV) ratio, and if you can find a deal where your total costs are low enough to keep the LTV within the lender’s limits. 

Just ensure to complete necessary due diligence - this can include, but is not limited to, title search, property inspection, appraisal and/or survey. 

Is there a limit to how high I can go? 

Being in the Army limits my ability to travel and explore markets firsthand.

If you dont have a great team to work with you can lose your shirt even if the house is next door to where you live... there are lots of great areas but only a limited number of great teams so our final choice has always been team driven... saying that we look for an area where there are lots of opportunities  and rental houses available in good areas using the 2 % rule  we found this in Detroit and Toledo  more then willing to share what we do and what we have learnt over the years

Many investors do end up getting their own license because of this, others don't want the liability and extra work.

Are you limiting your SFH to Duplex conversions to properties that do not require an architect? 

When I went to cancel my membership, RentRedi gives you a large box in which you can describe to them why you decided to cancel, and there was a SHORT and hidden character limit!

I have considered adding an ADU in the back, but since I am limited to 75% of the main house square footage, this is also probably not worth it.     

there just aren’t many sold properties in the neighborhood in the last 3 months and even out to 6 months is limited.