I was advised to potentially seek a signature/personal loan and pay for the home outright, however, would I not run into the same problem when attempting to refinance into a conventional after rehab?

As noted, hard money is expensive money, so I attempt to draw as little as I can.

Hence a lot of agents not using or accepting escalation clauses anymore and just going with "highest and best" to attempt to streamline the process (escalations were popular in my market a few years ago but it's common now for listing agents to discourage them and simply ask for highest and best).

I have never attempted anything like this.

Assuming I want to attempt it, does it take a long time to take ownership or is it a fairly easy process?

I find PropStream to be an amazing tool, however when attempting to import PropStream export into my crm it’s like a square peg into a round hole.

If they attempt to come after you for money, simply ignore them or hire an attorney to set them street.

But that might be your only solution if you're wanting to avoid and attempt to 1031. 

I then explained to him that he does not have a contingency, and he is breaching our contract by attempting to cancel simply bc he was offended that I asked for a repair credit.

I have had at least 4 or 5 attempted scams from guests off of VRBO but never the other platform.