I transferred the money via EFT (the transfer instructions had no reference to Lendbase - red flag), and asked for a receipt, but was told that their customers rarely ask for a receipt. 

No one's perfect and honest mistakes happen and a PMC often needs guidance as to what level an owners wants to maintain their property.Wasn't trying to solicit your business,so I'll respond via DM about the rest of your questions:)

So far it sounds like we will just need to verify via a CPA, which is fine, if that is what we need to do.  

I would also join a bunch of Investor groups via facebook and try to connect with as many people as you can. 

If you're W2 but hourly and "variable", meaning you don't consistently work the same fulltime hours each week, then you'll still have to average income over the past two years and may not qualify at all, depending on the circumstances.What will not work is using an S Corp to pay yourself via W2.

In some places there are a few days grace period to allow for rent that is sent via mail (which I don't get because if it is due on the 1st, plan ahead). 

Be sure to follow all formalities, such as sending via certified mail if required.Transfer Rent Payments: Notify tenants in writing that rent payments should be made to the new property management company moving forward.

I offer an online payment portal to submit rent payments via ACH or CC - they "couldn't figure out how to use it" so I set us up to accept Zelle payments.

At the end i will add a list of items why adding a single ADU in single family zoned areas may not be the best RE option.The most common value add is via a rehab.  

You should definitely be able to at least find yourself some solid realtor options via bigger pockets.