If I understand COC correctly it should be $3,276/-20 or -16300%What a I missing? 

USDA does not allow you to refinance from any other type of loan to a USDA loan so you are unable to get a USDA loan.You are trying too hard to understand this all and you're missing a lot of things. 

Never missed a payment and was never late.

Expect some mistakes and redo's along the way to add to the time.Expect any government inspections to add to the time.If you can keep the same team all the way through by the time they get several units under their belts they may be able to go faster--providing they can get the materials.In my opinion, it's more intuitive to look at each unit as a separate job, vs demo all kitchens and tubs in X units as a job.They can still come and demo several units, just for me it's seems easier to keep the Tiger by the tail this way.If you buy all of the materials at once, you will have to guard them against theft and store them somewhere. 95 toilets going missing probably won't tank your budget, but it might tank you enthusiasm for a while.Make sure to budget for a dumpster if you need one, and porta-potties for the workers to keep them from using the ones in the units. 

Am I missing something?

3) What negative consequences could I be missing?

You have some good advice here and some spam, but most are missing the most important thing for house hackers right now if they are using an FHA loan - it's vacancy.

If there was a roof leak that destroyed the living room, they can't just patch and paint the ceiling and then a month after your purchase the ceiling caves in again.

I feel run-down thinking that if I put all my time into career/investment building that I’ll miss opportunity to build community and find a life partner.

However would like a little bit of confirmation i suppose to build confidence as well get pointers of what ive missed from the experienced.