There isn’t anything different about the creator program payouts from typical partner commissions. Task payouts will appear as pending actions according to the immediate locking and clearing schedule defined in the contract.
No, you aren't required to use tracking links. impact.com gets social insights per post like shares, likes, engagements, comments, etc. without using links. You'll need to use links or promo codes to track performance. It is possible to track performance even if there is no associated payout for the campaign. So, if you're doing flat fees only you could still use links to track performance.
Performance by Campaign Report
Yes, a template term is always required to create a relationship with creators regardless of the campaign compensation type.