I can agree that finding comps for a triplex would be much more difficult than SFRs in the same area.  

It will be very difficult to get a great deal with a mortgage .

Too many parties that can potentially make your life difficult.

Otherwise, I would have kept renting it and getting one of the worst cap rates in the country in San Francisco (~3.8%).

However, as you said, this may be market specific and in some markets the purchase price is so high vs. rents that it may be difficult to House hack and make it worth it. 

I'm usually very wary about partnering with a contractor, seeing as how I got screwed over by one at the beginning of my real estate career that took 2-3 years to recover from.If you own the lot free and clear, it shouldn't be difficult to get financing for 100% of the build costs (feel free to PM me). 

Usually they're capped at 75% ltv.

Difficult to advise base on sketchy information provided.

As I look at the current asking prices and run numbers, I am not finding anything that makes sense. (1% rule is not happening and cap rates are like 4.25%-5%)I am new to this world, haven’t made a real estate purchase yet, but I am interested in meeting people in the space and learning as much as I can.

Going off your wholesalers pro forma and assuming $175 lot rent (@Ryan Groene could tell us if that's on the high or low end for a mid west park) This 6 plex has a 18% expense ratio and is selling at a 19 cap.