If you don't like the new Father Winter, you could go to Manage Households and delete him. A new one should spawn. That is weird about your Sim disappearing. I wonder what would happen if you deleted Clement Frost, maybe a new "Father Winter Clement Frost" will spawn. I think you can add Father Winter's visit to a custom holiday, so you don't have to wait until Winterfest comes around again. I agree with you, the new Sim doesn't look Father Winter-y at all!
Also, apparently the refusal to give presents to a toddler might be a bug. I've heard other people mention this issue.
