@Derek KroegerYour first choice should be to find a CPA that specializes in real estate taxation and one that is local.

Keep in mind with rates dropping on cash out refinances since they reduced the LLPA hit a cash out refinance may be a better choice over a HELOC.  

I was initially thinking one of the light gray vinyl plank choices, but wondering if that would clash with the existing flooring at the transition (by the breakfast bar in the photos) Any advice would be appreciated!

@Scott Pillsbury There is Very Specific language in your contract detailing your financing contingency, timelines, what happens at certain dates, seller and buyer choices and requirements, etc.  

FASB allows for a choice of either but it is very difficult for public companies to change from FIFO to LIFO or LIFO to FIFO.

If so, is my choice then only to do offline one-time payments through Zelle/Venmo/Paypal, etc?

Seller agent offering 4% to the buyer agent to begin with, wow...Anyway, at the end of the day the choice for the buyer agent is to either take $11k on a likely successful closing, or take zero because you can't meet the new bid price and he has to start over again to find you a new deal. 

When it comes to exit strategies, it is definitely a wise choice to choose a property where the LTR rental rate will at least break even for you; however, there are plenty of investors who take the risk of going all-in on the STR exit strategy when all other exits are not projected to be profitable.  

You have two choices, demo the entire lid and add new drywall or get a good drywall crew to skim coat the entire ceiling.

Like with any choice, there are trade offs.