Hey GK,
Its great to hear from you.
1. Triggers are for timed events like happy hour. You would use Rules & Actions to apply a discount when a staff account is selected.
2. You would settle to the staff account, then clear the account thru cash drawer.
3. All transactions will show on the reports because they are a sale.
V2 doesn't give you control on the spend, so staff could over spend.
V3 allows you to run credit accounts so the staff can only spend what is available. It has better control over discounts, but all sales are still recorded.
You can top up their accounts manually or by rules and actions, and you can manipulate the accounts to hide these transactions from the sales figures - but they still will show in the WPR & ISR reports.