I already have some equity in the property after doing a complete rehab but I don't want to diminish my returns selling it after one year, paying for commissions/closing costs.

Buyers may just factor in flood insurance costs. 

A friend and I created one recently:https://drive.google.com/file/...It was meant to compare costs between different lenders, but you can use it to just see costs from one lender as well.

We're looking to gather info about likely cost, pitfalls, time required, considerations when obtaining financing, etc. 

We agreed, and then they informed us after the fact that the cost end up being $2,000.00 because it was "so dirty." 

What add cost should they expect?

We are considering building and holding townhomes but need to determine the costs.  

10k Course, Sub 2 an inner city boarding house, Cost Seg, Cook Islands Trust  Naa, you forgot a step: after the sub2 and before the cost seg you need a G6

Renovations that truly add value-like modern kitchens, open floor plans, and energy-efficient upgrades are making the difference in selling faster and at top dollar.Financing & Interest Rates: The higher cost of borrowing has made tight budgeting more important than ever.

Also, you didnt mention any financing costs, was this built with cash or do you roll that into your cost of construction?