One of my colleagues house hacks himself, and I plan on doing it as well once I can get the cash to put money down!

well this one sounds like if the info is accurate money was collected and just absconded with. 

I would imagine they wouldn't be too appreciated of that and would put up a fight although they signed a legal contract to sell for $x.I had actually put a nice lot under contract (I was going to close under my name as normal) from an owner that was doing a FSBO.

When they don't take advice and call it criticism or call us mean, what they are really doing is putting a light up into the sky for all of the gurus to come collect them and their money.

It's sell, take the 100k profit, your at 360k in the bank, VTSAX or money market and chill for a bit, see how this market/economy thing plays out, rates have to come down no one can afford at these rates, then maybe look to refi and get the rate under 5%.Also something to think about.....

Would I actually need to worry about a balance transfer fee?

It's the best way to gain experience, work with buyers and make money while you're growing your business. 

I saved money from working as a realtor and invested my own capital as a limited partner.

An experienced property manager should also be able to help you net more money and will handle the marketing, leasing and background checks.

.- It barely squeezes out any money per month.