Meanwhile he's going to be wanting his deposit back. 

Worst case, I can look up zoning changes and match the address with recent sales, however, if no permits were pulled I do not know if renovations occurred further increasing the value.

This is unless you are allowing your buyers to go under contract and conduct full diligence which I can't imagine you are allowing since it would put your deposit money at risk, correct?

But how do you know what to take out every month from the bank account once the rent checks are deposited? 

You want Tenant A out, you inspect, you handle the deposit, then you move Tenant B in.

As a seller I would counter your “certain to close argument” with “great, I want a $20k, or higher non-refundable earnest deposit.”

Is that 5k left to pay on top of their deposit amount?

It's easy enough for me to use myself and has a lot of other features that help me manage my rental portfolio and take more of the day-to-day management in house, like vetting tenants, collecting security deposits and rents and its other banking features.

I'm not sure if Baselane has a limit but I have one account per building + security deposits so would need at least 10. - The ability to create online debit cards has helped a couple of times but I'd categorize this as a nice to have. - Free would be nice but if it's paid and has extra functionality I would consider. - Interest earning (not a ****** 0.2% either).

We gave the builder a 25K deposit - but they've only gone out there one day and didn't break ground.