** EDIT: see my additional comment below, which contains a revised answer from CRA. This answer is not totally correct **
I called CRA. The agent I spoke with confirmed that these items are correct:
- use category 2
- cost amount is zero
- report RSU amounts under gross income
Regarding previous year RSUs under $100,000: the agent said that this did not need to be reported in T1135 for 2019 as it was not part of my income for 2018.
Regarding gain/loss on disposition: Documentation from my company indicates that the ACB should be calculated using the fair market value and number of shares on each vesting date. That makes sense to me since the gross amount of the RSUs were already reported as income in box 14 of my T4, and withholding taxes were already deducted by selling shares to cover the taxes (box 22). If ACB was taken to be zero, the disposition would basically be double-taxed.
