I've had success with 2 short-term rentals, and wanted one more in relative close range to work and life.

Google search gives me these super wide ranges and mostly talking about adding a bedroom in a SFH, which I'm not sure if applicable to this situation of "moving/subtracting a bedroom from one unit and add it to another unit in a duplex". 

Hello Everyone, I am seeking a lender to help me refinance(conventional loan) my manufactured home.

The bigger the property, the different the agent on the commercial side.Multifamily in the 10-30 door range 

Investing in multifamily properties in Philadelphia is popular due to the city's steady population growth, job opportunities, relatively affordable property values, and solid rental demandPhiladelphia’s multifamily market offers a range of opportunities, from high-end neighborhoods to up-and-coming areas with great cash flow potential.

A lot of people shrug off Modular and Manufactured but they are both cash cows and help avoid longer construction times, higher material costs and less permits. 

In my market I think $2,000-2,500 might be the range I would use but your market may differ. 2.

As mentioned above your new rate should actually be 6-7 range not 8s so shop around.

The range of IRR's syndication/crowdfunding deals is much wider than just 15-18%.

Also pricing tends to be in the $250k+ range for SFHs, so cash flow may be difficult depending on how one is financing the deal.