i think your best bet is to try to build a network within the investing world so you're positioned as a hub, someone who knows a lot of people, and see a lot of transactions.  

It's hard to say for sure without knowing your market numbers, but I would bet you if you looked at a 10 year projection, you will probably have a better ROI with the equity in 2 houses as opposed to the equity and cash flow with one. 

15 acres for a lot sounds huge to me and I'll bet you could be missing out on some extra $ by not getting more lots.

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I’m also not a fan of buying a property that loses money every month, while hoping for appreciation and betting that interest rates will fall.

It has been mentioned above but your best bet is to separate the SFR and the 8 unit into two separate transactions.

If you can hang on into next spring/summer I bet you'll get better rents or be able to sell.How about asking your lender to push a monthly payment to the end of your term for the purpose of fixing the asset?

His suggestion was to wholesale it because he believed that for the purchase price of $90K, it'd be a relatively safe bet with a good margin.So, my question is: How do I get cash buyers or "buyers lists"?

A local broker will be your best bet. 

Your best bet at this point is to get together with an architect and see what your options are.