Are RSUs sold to cover taxes considered short term gain?

-When some of my RSU were sold on vesting day automatically by Fidelity to cover taxes, will the remaining amount left over from the sell be considered as a short term gain?

 

-Should my total cost basis be $0 for these tax related RSU sells?

 

-If multiple RSU grants vested on the same day and each grant had some shares sold to cover taxes, can I consolidate and report all the sells on that day together as a single batch?

 

Thanks.