vaccines, winter lambing, I'm in a pickle.

I purchased 14 beautiful tunis/hair ewes in September. The woman I purchased them from threw in a nice ram with the bunch. She said he has been with them for a few cycles and they all should be bred. She also explained to me how she winter lambs.... I did not put 2 and 2 together. I was completely expecting an early spring lambing season (and excited for it!). Our plan was to lamb on pasture.

While feeding bales this morning, I noticed that one of the ewes is starting to bag up. (Theses are all yearlings) Her vulva is also pretty swollen. She has a smaller tail and so I can get a better look at her than the others. A few more of the ewes are starting to bag up a little too. So I guess I will be WINTER LAMBING!

It is 60 outside today and sunny, I have lived in Missouri for 6 years now and so far the winters have been pretty mild. If anything it doesn't get cold until after December, Mid-January.

Can we still try to lamb on pasture? Our old barn has stalls in the middle (2 long feeding areas on each side) but thats it. I don't really have a setup for lambing in a barn. I figure as long as its not too cold, we can keep them out there. Currently, there are in electrojet on pasture. We panned on moving them to their winter paddock, attached to the barn, in January.

Also, I was planning on scooping up the lambs to tag, castrate, vaccinate, and (maybe or maybe not) dock tails- I still can't decide on that one) within 24 hours of being born. None of the ewes have gotten a CDT shot since we purchased them, and I have no clue how far along any of them are. SO can I and what do I vaccinate the lambs with? The internet has throughly confused me and ,honestly, I don't care for our vets opinions when it comes to sheep. I would vaccinate the ewes individually as they show signs of lambing, but that are very skittish towards me still and I have to stress them out so close to birth with our primitive sorting method. (currently we put them in a small room in the barn, close them in with pallets, and grab the sheep we need. - were waiting for our neighbor to have a day off so he can help us put together a corral)

basically I need wisdom on:
-lambing possibly on pasture/in a our barn over a long season
-what to vaccinate the ewes since their mothers don't have their shots.

If it is safer to lamb in the barn, How can I set it up so that they are safe and comfortable. I attached a drawing of the barn, I don't know if that helps. We also have no guardian dog, just electric fence. We have had no issues this year but I know that winter is worse for predators. If we keep them out of the barn to lamb, should we consider getting a dog? We were planning on doing so in the spring anyway.

thank you all! you have been so helpful to me as I attempt to start our farm. I really appreciate it!

Lambs are pretty cold tolerant as long as they can get dry and stay out of the wind.
But where you have a barn available and want to handle the lambs soon after birth, it would make sense to let them lamb in a stall. Then they can bond with their lambs without all the other sheep around. Especially if they are first timers. Usually 24 hours is enough time to bond in my experience.
If you put your electronet where they have access to the barn, they will probably segregate themselves into the stalls or a quiet corner as they get ready to lamb.
As far as vaccination I would go to the website Sheep 101-201 and do what they recommend. I have not been vaccinating mine but will this year so I can sell the lambs easier.
Good luck and happy lambing it is an exciting time. Post pictures of lambs if you have time.