Pre-Fab experience in/around Detroit?

[Brian Kantor]

Hey, there. Currently a buy-and-hold investor in and around Detroit closing in on my second rental. Was recently introduced to the concept of pre-fab construction and was wondering if anyone had any experiences to share (either positive or negative)?

There are a ton of empty lots across Detroit, which seem in theory like "easy" places to pop up a pre-fab SFH or small multi.

I did some preliminary research here and via Google and see that most people's experiences seem pretty positive with key draws being the cost = less than or equal to standard construction, materials being eco-friendly and sturdy, shorter construction time, similar appraisal value, to name a few.

My questions:

1. Can anyone share any experiences specific to Detroit or the surrounding area with regards to permitting or legal pitfalls to avoid or hurdles to jump over?
2. Process: Do you hire both a pre-fab manufacturer AND a GC to stitch the pieces together or are they one and the same?
3. Specific vendors that service the area with a good reputation and experience with small multi-unit in particular?
4. Is the mortgage process any different than with buying an existing structure?
5. Cost? I know there is a range, but for a four-plex for example of 4000-5000 square foot, what can I expect in hard + soft costs?
6. This may be a dumb question, but are these usually built on slab foundation or with a basement/crawl?
7. Does this affect tax assessment in any way?
8. Any other points of note?

Thanks in advance, and Happy New Year!