Quote from @Heather Luu: Unfortunately, you would have to re-key the locks.Here's another option.

Regarding price, do you have any suggestions on how I can get him to agree to a lower price?

FYI, a 203k FHA loan is not a DIY-friendly option.

@Susan Tan you may also have lending options in the Houston area that offer 100% LTC financing for rehab projects.

Having the info will help you weigh the options and make an informed decision.

If you do have to move because of a job, you would be safest (in my opinion, i am not giving legal advice or financial advice), i would sell that property to ensure that you did not just purchase with the goal of moving out early and taking advantage of lower rates and lower down payments for purchasing your home as a primary residence. 

I'm confused at to why some folks on here are saying that adding an ADU will lower my property value.

Always consult with a qualified tax professional before making any tax-related decisions.Depreciation losses will have no effect on your financing options. 

For investors, the current market presents a mixed bag: while short-term rental income may be lower, Miami remains a strong market for long-term growth as affordability attracts more tenants.What’s your take on Miami’s rental market?

that we’ve learned in our 24 years, managing almost 700 doors across the Metro Detroit area, including almost 100 S8 leases:Class A Properties:Cashflow vs Appreciation: Typically, 3-5 years for positive cashflow, but you get highest relative rent & value appreciation.Vacancy Est: Historically 10%, 5% the more recent norm.Tenant Pool: Majority will have FICO scores of 680+ (roughly 5% probability of default), zero evictions in last 7 years.Class B Properties:Cashflow vs Appreciation: Typically, decent amount of relative rent & value appreciation.Vacancy Est: Historically 10%, 5% should be applied only if proper research done to support.Tenant Pool: Majority will have FICO scores of 620-680 (around 10% probability of default), some blemishes, but should have no evictions in last 5 yearsClass C Properties:Cashflow vs Appreciation: Typically, high cashflow and at the lower end of relative rent & value appreciation.