Bought with 100% occupancy with 2/3 reliable tenants and the other one's lease ending soon after purchasing property.

You can have 2 identical properties next to each other but have a $500k - $700k difference in value.4.

Garbage disposals.are just notoriously low reliability.

Anyone know any reliable licensed Contractors in the dmv area that would be a good fit for a new business?

In fact, as an investor, your offer should not differ in price, because your ARV, and all in costs are going to be identical (somewhat) whether you pay cash or mortgage it (I am clearly ignoring interest and loan closing costs on mortgage, but also ignoring your cost of capital for cash).  

So, in your example, if two homes are identical in every way except the subject home is 3 bedrooms and the other is 4, so long as a 4 bedroom home is viable in that particular market then you would expect to see a slightly higher value out of the 4 bedroom than the 3.  

They would be more reliable at maintaining the home and payment than a tenant ever would be.

NOW, ( My personal opinion) In my advantage (I'm a license realtor, 90% of my business is on the investment side)  the only thing it really helps me I've seen is that only provide legitimacy, reputation reliability , professionalism and some authority, IN front of other investors or partners or sellers (JUST for the fact I have a license, Not the knowledge gain on  the test ...) 

Airtable, a good CRM, UpWork, and a reliable handyman-What pitfalls should we try to avoid?

The downside to this is I didn't predict the separation nor the pandemic, so I'm left in a position where I need to have a more reliable source of income (ie not commission only) and I'm quickly running out of financial runway.