For a standard mortgage closing, what parties are usually in attendance for the final walkthrough and closing event?
The buyers and sellers are represented at the walk though. The person who represents each side has to have the power to address any issues. If there is a surprise that has to be addressed, then delays while getting permission will impact the closing. Not all buyers and not all sellers must be there, but both sides need to be represented. Frequently the real estate agents also participate.
Closing is a separate thing. Everybody that has to sign a form must be there, or be represented by somebody with power of attorney.
I recently sold and bought in NJ. Closing during the purchase was handled by my lawyer. I didn't attend but instead signed a few days before.
When I sold, I attended the closing with my lawyer, my real estate agent, the titling company, and the buyer. My mortgage broker showed up as well but wasn't necessary.