I also require additional security deposit and sometimes a guarantor if they were approved in this manner.I also agree that this situation sounds like a pattern not a one-time mistake or short term tough situation that caused this.  

The real prohibitive costs come from the legal, compliance, and reporting requirements of registering a security.

Looks like a good service but they seem to require a minimum of a 100 doors?

A land loan for 'raw' land will require a 50% down payment and high APR as you know.

The management company just didn't do a good job of providing details on bills and never checked on the units.

If the lienor failed to follow the statutory requirements to perfect the lien, the title insurer will probably advise the management company of the problem and request they record a release. 

Wholesalers are not regulated by Real Estate Agency, therefore not required to abide by certain laws and disclosures.

The lease should have a provision that requires the T to comply with HOA rules.

A BRRRR could maximize returns by recycling capital, but it requires solid execution.

Assuming 7.5% interest rate, the negative leverage would require you to put way more than 20% down just to break even.