How big is your proposed enclosure Ed? What breed are you proposing getting? You need to watch for electric mesh as sheep can and do get stuck in it, and you can't use it for horned stock at all.
I understand why you want to keep the lambs at foot for breeding in the future, and by using ewes which have previously lambed you should have few problems.
For weaning, you really don't need to separate the lambs off. The dams will wean them off themselves and their milk will dry up naturally by 4 to 5 months. This still gives them time to have a couple of months to get into condition for tupping, and is far less stressful for ewes and lambs both. If you really want to wean them early, then you will get different advice. Some say to move them as far apart as possible so they can't see and hear eachother. As in reality you can hear a bawling ewe about a mile away, I use the other method where I put the lambs in the next paddock. That way they are near their mums and can even walk along beside them to graze, but just can't get to the udder. I wouldn't use electric mesh though as the lambs will try to push through and will certainly get caught up and can easily strangle in the stuff.
Yes, if you are going to breed your lambs at 2 yrs you will need to keep them away from the tup this tupping season. Could you borrow a tup for a month at the vital time from one of your local sheepy friends? That way you don't have to keep him around, and worry about him being on his own.