Apart from the wether being endlessly humped
there will be no problems. Generally, where a younger animal is introduced to an older one there is no problem. The younger will automatically be submissive. I wouldn't think you'd need to do the penning them close either.
When we took our tups (4) out from the ewes, we popped them back together with a handful of tup lambs and wethers, without all the usual palaver of penning, and after greeting each other happily, the whole flock settled back down to graze. The two oldest tups had a very desultory horn pushing session, but there was no animosity to it, and the field has been sweetness and light ever since.