I recommend getting a scope of work from your PM while you're still under contract so you have an accurate estimate of what your rehab costs will be.   

I have a loan estimate from a lender that increases the loan amount by ~$3500 which essentially cancels out the out of pocket expenses, and reduces my rate to 7.5%.

During the pandemic zillow was giving more estimates but IMO they were off.

Just wanted to ask if any investors in the Austin/Cedar Park area with experience in rehabbing with today’s constructions costs had any general tips on estimating rehab costs for a property? 

Now Zillow estimates the value at $210,000, so Greece houses have appreciated nicely in the past three to four years.

Scott The Book on Flipping Houses, The Book on Estimating ReHab Costs http://www.biggerpockets.com/flippingbookConsider checking out HUD homes for small multi's owner occupied gets first crack.

And if you're investing in a syndication that typically produces K-1's late in the tax season (such as a GP fund) this can make things very tight and/or cause extra tax bills from having to do estimates extra tax work with your CPA.  

Also see if you can pull up rental  and sold comps in the area using Zillow and Redfin and you have to give a   margin of error in their estimates and see if property appreciation is there for that area in case you are thinking of building equity.

I ended up spending HOURS building a tax estimate spreadsheet.

They can help you find a good cost segregation firm and get you a free estimate.