I have this issue with Buildium for all the online rent payments received through their payment app. 

I imagine a T-6 is just a Trailing 6 month table that shows our rents, expenses all fully tabulated and organized into a summary table, but having a hard time finding documentation online to support that. 

I just set up a SDIRA and am looking for advice and tips on opportunities to invest.

. :) It sounds like you are looking for a specific investment opportunity? 

We have investors and opportunities in both of these cities as well other some other similar markets not too far from there.

If I am self managing my portfolio, what do I need to check/confirm, and what easily available tools are at my disposal (online, other) to help me do this? 

You can also check their reviews online at Google, Facebook, or Yelp.

I’ve been shown no evidence that there was fraud, nor that the sale of the investment opportunity was not in compliance with either the General Exemption for Private Placement or Reg D safe harbor.  

Quote from @Simon Walker: Quote from @Brandon Croucier: Opportunity cost is a serious expense, if they are moving slow, they are COSTING you more money than what a hard money lender might able to make you.

If you do not find success there, there are some online companies like SpaceJoy, Decorilla, Havenly etc.