There is traditionally no waiting period for a rate/term refinance.

.- Address buyer's concerns with reputable local professional and expert evaluations and written estimates.For example if the deck needs to be repaired or replaced, during the contingency period I'll attempt to have at least 1-2 licensed contractors provide written estimates.

The DOS has a very short time period to cure.The guy who bought sub to, no longer owns the property.

A few of the crowdfunding sites have proven to be quite effective and efficient. 

Sellers need to provide certain records, as  requested as part of the contract within a due diligence period.

If you have that much cash it would actually be more efficient to purchase a pre-existing fourplex, put the 5% down and get some concessions to buy down your rate.Hopefully that all made sense.

-Using the city water bill, it's an issue at move-in and move-out to prorate usage since the tenancy won't line up with the billing periods.

Want predictable efficient results?

Period. 

@Tim Porsche - disclaimer - I know nothing about Pennsylvania real estate law.That said, I don't see any recourse for you here on this issue, as they would likely argue that you had a chance to do your due diligence before writing the offer and/or could have written a due diligence period into the contract and chose not to.