Best of luck to you working through the renovations - if you need any design advice, feel free to reach out!

Also, it goes without saying that if you make a procedural error (very likely as the process is designed to trip up the unsophisticated landlord, and all tenants have the right to a pro bono attorney), then you have to start the process again from scratch. 

That way you can work backwards on the land price AND your holding costs while you're designing, permitting, and building the home. 2.

Advice on Layout/Design: For those who have added ADUs, do you recommend standalone units, garage conversions, or a combination of both?

Get a good architect first and design what you need don't jump the gun. 

During this time, we aimed to provide comprehensive support, including design, setup, and data-driven projections.

For my personal properties, I design the mortgages so that I'm just above cash flow neutral. 5% of the gross income is a good number I shoot for above neutral.

And don't forget to factor in design/furnishings into your budget keeping in mind your ideal guest avatar.    

Yes, it is possible to obtain a second FHA loan, but only under specific circumstances, as FHA loans are designed primarily for owner-occupied properties.

BiggerPockets is full of resources designed to help you along your journey, whether you are just getting started or a seasoned investor.