-If it's determined that your Alderman would be supportive of your 'plan', and you've already connected with a local architect, you'll then want to reach out to a zoning attorney.

That will largely help to determine the right fit in the landlord market for someone with a portfolio. 

Lease Terms: Determine a monthly rent payment that covers the HELOC repayment (interest and principal) while providing some positive cash flow for you.                    

As others have stated, you have not provided enough information to determine whether this is a good deal or not.

For me, the first pass at underwriting is simply about determining if a deal is worth exploring further.In the current market, I’d say 9 out of 10 deals are dead on arrival.

From my understanding, as long as you intend on doing a STR when you close, there are no rules against changing your strategy after closing, especially if you find that something else is more profitable.So in our case, the lender determined an STR would bring in ~$3500/month (with all of their conservative factors), but now that we operate it as a huge 3300 sqft Co-Living property, it actually brings in $7000/month.

I am a complete rookie zero experience, zero properties and highly determined to get into multi-family investing.

Quote from @David Hori: I've been vetting gurus to determine where an investment would return the greatest ROI. 

You need to determine the best route for each deal you do. 

To determine what to offer on a rental property:Determine reasonable market rent, NOT the highest!