The New York Fed runs a daily "multiple-price" auction using the FedTrade system which allows primary dealers to submit orders to sell shortlisted Treasury and agency securities at various prices. The Fed chooses which orders to take which is why "accepted" is lower than "submitted". Orders are selected based on price.
Par Amt Submitted: Total amount (at par value) of orders submitted by the dealers during the auction, for a given security.
Par Amt Accepted: Total amount (at par value) of orders accepted by the Fed during the auction, for a given security.
Total Par Amt Submitted/Accepted is the grand total for all securities traded during the auction. In the Excel spreadsheets, this column repeats the daily total for all securities.
As far as exclusions - the above link elaborates that exclusions are operational and are based on market criteria such as specific bonds going special in the repo market.
Par Amt Accepted is greater than zero, the
Weighted Avg. Accpt. Price/Rate should display the VWAP price or rate. N/A seems to be a bug.
Update 1: N/A values in the most recent report appear to be present by design. They're replaced with actual prices after some delay. Perhaps Treasury Ops is masking unsettled trades to reduce market impact. Also, you might find their API endpoint more useful than downloading Excel reports. Data prior to 2020 is sketchy however.