Do you work with any specialty tax firms to help us small business owners get access to R&D tax credits, cost segregation and other specialty tax credits?

SMALL BUSINESS ADMINISTRATION 

As you progress your bookkeeping business, you'll likely want to learn how to export statements from a variety of property management platforms, as investor books are housed in bank accounts, spreadsheets, and a variety of property management and accounting software!

My significant other and I decided to use a builder she had done business with in the past.   

Bigger Pockets is a great place to find a real estate tax accountant.A good real estate accountant can save you thousands of dollars by leveraging entity selection and formation, tax deductions, cost segregations, bonus depreciation and tax planning.I recommend finding an accountant who specializes in real estate taxation, business taxation, financial planning and tax planning.You may want to consider working with your accountant remotely to expand your options.I would also recommend looking for a accountant willing to work with you throughout the year.

Always do your due diligence folks, search for their name on here, check for criminal and civil court cases in the county they live/do business in, etc. 

We have built a very similar business here in Austin.

Are there any potential risks or downsides I should keep in mind before proceeding?

My only reply here is to say to simply focus on the business objectives.

I would greatly appreciate any guidance or advice starting off with this business model.