I seriously don’t think cold calling a list for wholesaling is effective enough for it to be worth it.

You better have a good understanding of what the effect of the docs are. 

I don't think I should count the missed principal payments as cash flow because that is in effect reducing my equity in my property, but what about the interest I would not be paying for those two months?

First, you sure have thought out some options...and finding the most cost effective solution is always best. 

If these are in mint condition... the electrical will no longer meet code, and I recommend re-wiring.The plumbing is a toss up, sometimes we scope lines and they are clean as a whistle; sometimes we scope lines and a 4" pipe has an effective inner diameter of 1/4"... just depends. 

Prices could also plummet in a few months when many are still not back at work and we have more fully realized the full effect this event has had on our nation's GDP.

My question is how likely are they or their brokerage to exercise that clause?

Help for Airbnb and Vacation Rental OwnersWhile long-term effects on the short-term rental industry are debatable, here are some things you can do right now:Reduce your vacancy rates as much as possible by offering discounts and being more flexible during this timeCut your expenses by eliminating welcome gifts, reducing amenities and subscriptions or applying for mortgage deferral programs, as discussed aboveIf you’re an Airbnb host, apply for cancellation reimbursement under the $250 million Host Relief Fund available for qualifying cancellations (up to 25% reimbursement of what you would normally receive from a canceled booking)Consider turning your short-term rental property into a long-term rental, at least for now, as the traditional rental market is not expected to be impacted as severely as the short-term rental market  Additional ReadingResources for Property Owners and Agents from the National Association of Realtors is a great list of general recommendations and resourcesList of Relief Programs Offered by US Banks, published by the American Bankers Association, is a comprehensive list of specific measures banks across the US are taking to help borrowers in needCOVID-19 Tax Resources Center by the Drucker Scaccetti tax services firmLegal Guide for Landlords by Julie Anderson, written for the Mid-America Association of Real Estate Investors, provides general legal guidance and advice for real estate investors  Please let me know if I missed anything, or if there is any inaccurate information, so I can correct it.  

Which website or service do you find to be most effective?

Here's an example from an actual BRRRR I did (except for rounding a couple numbers to make everything easier for this exercise):REFI LAST:Purchase w/cash: $25,000Rehab: $30,000ARV: $100,000Loan (@ 65% LTV) = $65,000Closing Costs: $5000PITI: $550Rent: $995Equity: 35%Out of pocket: $0 (actually made $5K)REFI FIRST:Finance $25,000 (w/20% down): $5,000Closing Costs: $5,000*Rehab: $30,000ARV: $100,000PITI: $240Rent: $995Equity: 80%Out of pocket: $40,000*This is probably going to be lower due to a lower financed amount...but still, hopefully you get my point :)