They seemed okay but also seemed very much focused on cash buyers only (first red flag).  

If they directed me to a site that had no new information and they never followed up with additional information; it was a red flag for me.

If they are on a month-to-month contract then you can give them 30 days notice of termination or to sign a new agreement.There are some major red flags.

The OP is currently exploring conventional rehab loans (presumably 203k or similar) which would indicate that he is intending to owner occupy, and therefore hard money loans are likely off the table (as most HMLs are not NMLS licensed and don't make owner occupant loans).That said, to the OP, if you're looking at a conventional rehab loan you're just going to have to accept higher costs, less flexibility, and more red tape.

Living in a red state has its perks :) 

People are generally referring to this type of entry as contra-expense or atleast that's how I interpreted.In the PA tax return, this line item was highlighted in Red and hence the question

The involvement of onsite management, often seen as a potential red flag, can lead to the property failing crucial qualification tests.

@Lenza McElrath        Generally speaking if ANYONE will not be transparent about the income that a property generates, that is a red flag.

HELOCS do exist for rental properties but you are usually capped at 65-70ltv and these will most likely require a full underwrite that takes into consideration taxes, income, dti and all the normal quasi-associated red tape.

The involvement of onsite management, often seen as a potential red flag, can lead to the property failing crucial qualification tests.