My concern/question is "Am I stuck with soaking half the rent indefinitely?"

If they didn't have the money prior to not-paying, how would removing their car make them pay?    

But you mentioned that the co-op is an investment property and not your primary residence so do you have some sort of permission to rent it indefinitely?

Depreciation is not added back every if you continue to 1031 indefinitely, which is my plan.

I will definitely use an agent for the next couple buys, and indefinitely for sales, but I'm looking to get more independent on the buy side.

Your ROI is a number close to infinity and you can repeat indefinitely - And YES - there are still deals out there that will work ... one just closed a couple of weeks ago in The Woodlands on MLS at about 70% of value and only needed light rehab - maybe $5,000-$6,000ARV - 177,000Sold - 123,000Rehab - $5,000Total invested - $128,000-$129,00080% refi - $141,000 Rents - $1,500-$1,600 My initial offer was $120,000 - They declined to counter - Now that I see the final sale amount, it irritates me that I was so close but missed the deal  

Now you're in a tax free state with tax free income.If you wanted to live in ID you could always do a1031exchange on your place right now which would allow you to indefinitely defer the tax on that that sale and then get all your portfolio together. 

Not completely avoid, but defer indefinitely.

It would seem to me that most subscribe to the philosophy that rates will stay low indefinitely, in part because that's the new precedent, but also because the Fed has to keep them low to keep payments manageable on our national debt.

Holding onto it "indefinitely" would definitely be a possibility as well as my strategy is currently for long term wealth through buy and hold.