The quadplex seems like an ok deal, but is the apartment going to dictate my rents and what the tenants should expect to pay for utilities? 

That is reasonable to ask for a 2 day extension.

Ive informed them I would be renovating the apartment extensively.

I believe the best way to go about this would be to utilize the HELOC as your new checking account and sit all of your monthly income inside it to reduce principal, which in turn reduces the amount of interest you pay and basically reduces your monthly payment every single month.

You need to do extensive due diligence to make sure the turn key company is legitimate and a good business decision.

Being that you're in the other unit, you'd be paying over $2,000/month yourself - NOT including taxes, utilities and capex. 

Account Closed yeah I've been selling a lot of fourplexes lately and they should all cash flow, even with appropriate numbers for vacancy, utilities, repairs, capital expenditures, and property management.

One of the big HOA managers in town retired a few years back and left his kids to run it, the downfall has been noticeable in communities they run (which is many of them). so do extensive due diligence.

Keep in mind your holding costs also will include utilities and insurance (I assume you plan to carry insurance). 

Residents pay all utilities.