Update:
Now we've got everyone back in the main flock with our Welsummer cockerel recovered from whatever caused his limp. They were first reintroduced through the fence for a few days and when the heat finally broke, I put them back together.
The two did of course have a big dust-up to decide who's in charge. Very small injuries- a little bleeding from the combs and one on the top of the head, but as soon as they were cleaned up it was very minor. Most of it was posturing and strikes at the air and jumping over each other. The SBEL cockerel seems to have taken the top spot. Last night the Welsummer was back in his old spot with half the teenager pullets-- tonight he's in an unheard of spot with the big girls on their favorite table with zero problems which was really nice to see- very peaceful. Not sure if this will last, but considering we're talking about two 21 week old cockerels, it's going pretty darn good!!