Just got off the phone with the zoning guy and he said since both of my lots pre-date the zoning regulations in the city, they're grandfathered in so-to-speak, which means I am able to build a single family on each one!

Will you be funding your own rehab or would you need to roll those funds into your initial loan?

Under contract to buy a home that needs to be completely torn down. I was planning on building the home in the traditional stick built style in my budget but am wondering if doing prefab may save some money/have other...

There is no additional "risk" on the note like a demand clause etc, but you have  extra expense in upfront one time costs and the pre-payment penalty that most programs are sold with if rates do drop as expected in the future.  

There were weekly group video phone calls that despite usually only having 5-10 people online I could never get a question answered leaving me to believe they were pre recorded.

I would say get connected with a local agent and also set up with a lender that has you pre approved to make it super easy making offers.

They'll roll up good reviews quickly and organically.Don't worry about manufacturing reviews.

You can take any proceeds tax free and roll into a different investment. 

No fees, no pre-pay.

I assume you currently have a residential mortgage that does not have a pre-payment penalty.