Thanks @AmyC / @fanfare / @SusanY1 / @RobertB4444
Since I asked many questions in this thread I will summarize here:
Cost Basis when missing in 1099B, use transaction statement. In my case I actually use my bank account to calculate the fees
Some brokers had horrible 1099B, like computershare in my case that force you to go through the whole history of transaction to calculate the endless fees along the way
Sell-To-Cover is explained perfectly above and had cause the same pain since it wasn't associated with cost basis but even more complex since money never come to my bank account so I have to search my paystubs!!
Spent in this process approximately a week
