We've been trying to rent this unique commercial building for months now, finally have a prospect but the previous use was small engine repair and the new proposed use is auto part retail.

The city is asking to verify with designer whether "Drag" truss is proposed on the design. 

You will likely need to initiate a Community or General plan amendment, provide a proposed use (sounds like residential), if that is more than 1 unit then you'll need a site plan, which would need a map to subdivide, requiring a 'Tentative Map', which then....and evaluate its impacts on water/sewer/traffic/greenhouse gas amongst others...The speed and efficiency of completing this does depend largely on the municipality, but if this is one of the big players (LA, SD, Irvine) then I'm really confident in my timeframe.

Especially in Houston you need to be careful about tax reassessments - the current assessment is well below your proposed transaction price.

In the case it is clear to me, as a non-attorney layman, that if you read all the documents, including the proposed advisory opinion (8/15/17) that the defendant was "...holding himself out as an attorney..." which is against Florida law. 

Want to check in with my BP "experts" to see if I'm reading this right - the public consultation is to determine whether to regulate the short term rental market for ADUs, which in many cases is currently illegal (or not explicitly permitted) under city bylaws. https://www.englewoodco.gov/government/city-departments/community-development/short-term-rentalsAnd the proposal is for owner/occupiers only to be able to operate STRs.Am I getting this right?

Bring your investor a lucrative deal/proposal. 

I seriously doubt that you'll find a Condo community that will permit the activity you're proposing. 

Just be aware if you go for a 3-4 unit there is a self sufficiency clause where 75% of the total proposed rental income from the units that you are not occupying MUST cover the PITI.

In that case, if the seller is motivated enough, which it sounds like they are, you could go back to them and propose that they hold the note for a year or two (maybe with interest only payments), giving you time to rehab and rent, and after that time you should have the equity and tax returns to be able to refinance into a conventional loan.