In the late 80's a Continental 747 departing LGW suffered stall on nos 1 & 2 engines due xwind, just after V1. Managed to get airborne. The F/E was dumping fuel even as the a/c was still on the roll & before rotation. The a/c just cleared Russ Hill 2 miles to the W then disappeared from view, whereupon the controller hit the crash alarm. The altitude readout on RADAR was showing 002 for a while; a cheer apparently went up when it read 003. The a/c returned & made an overweight landing. The rumour that twigs were found in the undercarriage are unfounded as they had the gear up before they got to the hill.
So, yes, you CAN depart after V1 & before Vr with a 747 with 2 out on the same side.
Cheers,
TOO