There are certain activities that an agent should not participate in such as using assignable contracts.  

I participate in a housing assistance program (such as DSS / Section 8) YES or NO (circle one) If YES, please indicate which program(s) assist you, how much they pay, and your contact person there: Program: ______________________ Amount they pay: $ ___________ Contact name/ph #: __________________ Program: ______________________ Amount they pay: $ ___________ Contact name/ph #: __________________6.

Are you getting paid for this work or are you participating in the profits?

Either you guys are partners (i.e. both of you are active participants in the investments), or one of you is active and the other is passive (i.e. an investor versus a partner).

Even a junior lienholder that participated in the 2MP program (Which was the HAMP program for junior lienholders, which is now defunct) opted in to the program voluntarily.

However, you can borrow from the solo 401k through a participant loan and can use those funds however you wish including for improving a property that you may already own. 

I have a condo unit where the HOA participates in a "crime-free" program where no one with a felony in the last 7 years can buy or rent a unit in the complex... point being it's been 10 years and he's had no other issues so I would be OK with renting to them. 

P.s I’m certainly on board participating in any local BiggerPockets events in Ottawa or Toronto.

@Alan FaitelNo as the solo 401k participant loan rules come into play.

If a trustee auction allowed any sale to be retroactively canceled and the buyer's money not refunded, I can't imagine anyone participating.