Simple answer - yes you can alter your funding source after putting it under agreement if you chose to use a hard money lender instead - i would just communicate with seller that hey I was going to use cash (assuming you have it from your heloc) and instead will finance some of it but let them know its not contingent on financing.

After analyzing the potential ROI, we negotiated a fair price of $58,500, ensuring room for renovation costs and profit.

The limit on scaling is your deal flow (mine never was that good) and time it takes to perform the value add (I got fairly quick for example, my last rehab did all new plumbing, electrical, and flooring.  

I do not find your complain about getting on their marketing list fair.

If they do, then you can likely find another tenant for that amount fairly easily, as I would assume the entire town's taxes are up- so if someone really wanted to be in town, that price is the new normal.If your taxes increased that substantially in a C neighborhood, your tenants would way more likely give push back for that type of increase- even though you're not being greedy, you're just imposing the same raise you were given.Often the buyer who had the "well, the numbers are better" mentality is only looking at year 1. 

Yeah fair enough.

Is communication prompt and reliable, K1 delivered on-time?

You're feeding 2 dogs with one biscuit by taking care of your living expenses and generating rental income at the same time, and by living in the house and keeping it to 4, you generally get exemptions on things that might bother you to live with (IE you can choose whomever you want as your tenants without running afoul of fair housing laws).

All fair questions and yes, there are far too many variables to say with any sort of certainty.

I also have ~$20k that I've resigned for the scripted "mishap" that always comes up after purchase...lolI've read a number of other threads and I've seen a fair amount of talk about Ohio.