Hi Sonjadaisy
Sounds like you are doing the right things. If they are over 450g they have a good chance to survive hibernation. There is never any guarantee, though, as it is a dangerous time for hogs. I would just keep offering them food, until they decide to hibernate. Although a few hogs decide not to hibernate and keep visiting all winter!
You could make sure there is loads of material around in case they decide to hibernate nearby. So lots of leaves, long grasses. They prefer medium sized leaves. Hoglets seem to be naturally expert nest builders, so you can leave that to them.
Good luck.