Does 64 × 200G/400G/800G mean every port runs at 800G?
No. On RG-S6990-64OC2XS that row is a speed range. Confirm the optic you will buy.
What does RG-S6980-128DC list instead?
128 × 200GE QSFP56, 51.2 Tbps, and 10,300 Mpps. It is a different faceplate, not a smaller version of the same row.
Can either replace a 10G leaf?
No. Use CE6820-48S6CQ-B or CE6885-48YS8CQ for 10G or SFP28 server rows.
What belongs on the RFQ?
Exact PID, optic speed and reach, quantity, and power. Do not send only “200G switch”.