We closed off the window and that remedied the freezing pipes as well.

Then, find contractors and get bids so that you can hit the ground running with remediation work after the tenants have vacated the property. 

Practical remedies?

I paid to have a mold inspector come out and while the spread of the mold wasn't severe, their proposed remediation is $2,000.  

I mentioned that while I understand the need for a vent, if it creates noise and disrupts our sleeping, then he would be responsible for remedying it. 

Mold remediation is not cheap and I'm sure there is at least one hidden surprise you would uncover if you did this deal, so be sure to add a 10% overage factor for whatever your contractor friend estimates. 

If it is determined to be an issue with a system not addressed during our renovation you will be free to choose any contractor you would like to re-mediate it at your expense.

And it wasn’t named that because there was a bespoke whiskey distillery for hipsters.

I knew any problems from taking on an average risk on a basic investment could be remedied through the awesome resource of Bigger Pockets and the few connections I had made up to this point.

There are multiple opportunities to remedy the issue, on both the tenant's and landlord's behalf.Regardless of how a landlord chooses to collect rent, they could experience the same thing that happened to you.