Note while HOA may allow ADU, might only for be for family, like in-law suite, no rental, so read docs carefully.

I’m new to Birmingham and was wondering if anyone has good information/recommendations for areas that are experiencing growth and becoming more pedestrian friendly.

Would certainly recommend visiting if one is close to you. 

And I just read that Detroit of all places is having a renaissance.

I'd recommend to reach out to Michael Estes here in Austin - he may be a great fit to help you with what you are looking for based on your goals/anti-goals listed aboveMichael EstesTexas RE Broker License #494994www.trendRE.com

I always recommend looking at multiple valuation metrics, not just one. 

Any recommendations?

Start reading about real estate and listing to BP podcast at 16 or so I just turned 20 and want to start taking more action and getting more involved in the REI community.

Cash out refinance is usually recommended if you are lowering the interest rate.

I also recommend you read this article I wrote for Bigger Pockets titled How to Invest in Real Estate Before Turning 21.