Many lenders have specific guidelines regarding late payments, but some may still work with you if you've made up missed payments and have shown consistent recent payment behavior.

Working with a HML requiring a non-refundable earnest money deposit…What due diligence do you perform before sending that deposit to minimize risk?

You can try and negotiate with them as well.If you have Been working with this agent I would not kick them to the curb. 

Use this experience to work out the kinks and build a strong boots on the ground team.

Just like the last comment, the list of problems we have is just too long to add here, but from the bad screening of the tenant to the work order that you pay and NEVER get done, you will need to inspect your property every time "they complete a work order." 

Is it true that this would make it harder for me to get a loan from a bank for the remaining balance?

If that doesn't work, then a DSCR cash-out would be a good alternative. 

Working our on capital stack for a large multifamily development and needing some different options with private debt/equity.

I work for a full-service brokerage that specializes in investing, particularly in working with non-US residents.

Play the 'friend in common' card if possible.Regarding seller financing, I don't see this being a viable option since they are in default on their current loan.If funding could be an issue for you, take a step back and work on that first.