The reason I say this is to lead into the answer from your question. 

I had an estimate done ($7k) because at this point the sprinkler piping is exposed and I'm afraid that could lead to an even greater problem.

You can learn to do this independently or get a rockstar REALTOR to lead the way.

Some say they are the same, others will exclusively do one or the other, which would lead me to think they are more different than first imagined. 

During this time you are not generating any return from the money invested in the ADU.

What I hear again and again from hosts who are accustomed to Airbnb for their STRs and even some MTRs is that they expect FF to work the same way when, in reality, FF is just a lead generation platform.

The right wholesaler that knows how to properly calculate a SOW (scope of work) to gain the rehab budget, generate an ARV from local comps and not want to get rich on every deal is NOT easy to find....but, they do exist.

You provide a service (offer), you find people who need to buy your service (leads), you need to close them in order to get their business.

(I have found a 2-1 that I can afford in a conservative 7% appreciation market)I’m also thinking about putting more effort into lead generation beyond just Zillow to expand my options.

It has a lower turnover than STR but can bring in higher rent than traditional leases.Co-Living Arrangements: Renting rooms individually on a month-to-month basis could generate more income than a single long-term lease while reducing management hassle.Furnished Long-Term Rental: A furnished rental could allow for higher rent and attract tenants who don’t want the STR commitment but still value flexibility.Partner with a Local Boutique STR Manager: Some local companies manage STRs with lower fees than Airbnb's traditional managers and could help keep profits up without 20% fees.Hope that helps you with your decision!