Repairs ($5k): Increase to $10k for unexpected issues in a 4,000+ sq. ft. property.Total reno costs will likely fall between $180k-$210k, not $145k.

Then the remaining profits get distributed at whatever split you both agree to...I often see it start at 25/75 (75 to the person in your position) and then maybe increase it to 40/60 or 50/50.It would really help if you could provide some numbers on your deal. 

Quote from @Basit Siddiqi: I personally would not buy real estate with a retirement account.There are just too many headaches that are not worth the potential increased return.Some headaches when it comes to investing in real estate with a retirement account1) LTV values are less and harder to find lenders.2) Potential to sell or partially distibute the property if you have to do a RMD(Required Minimum Distribution)3) If you run out of cash and have to make a major repair, you may be out of luck and have to sell.4) Having to potentially worry about UBTI(Unrelated Business Taxable Income)I would personally invest in stocks/bonds/notes with a retirement account.I buy deals with cash and use a ROTH SDIRA so there are no RMD's.I buy at huge discounts to retail.

Over time, rents may increase, improving your cash flow, and you’ll gain equity and valuable experience managing tenants and property operations.

Duplexes provide privacy, flexibility, and scalability, but strict short-term rental regulations may increase upfront costs and maintenance.

At that time, i will have the knowledge and network to expand and build my portfolio at an increasing speed and then it will be part of my growing pains for my business.I will most likely have that CPA do my returns for the real estate and then have my Tax Accountant still do my Personal, helps with Checks and Balance and cost savings.Do you have cost segregation, or anything like that on any of your properties?  

It's not that different from a normal rent increase.

The population continues to rise, increasing the demand for housing.

Cost of value add was $120k, so over $580k of increase above costs.  

Accessory Dwelling Units (ADUs) are an increasingly popular way to generate additional rental income on an existing property.