I like Keith's advice if you do decide to replant them this fall, have your bed prepped before you separate the cloves, and water them in.
I lost some shallots that I divided and replanted when green and late in the fall - I think frost heaves got them. Planting deep, watering in, and mulching well would hedge your bets.
OTOH, If the main purpose was to maintain the variety, and concern about surviving after growing green in the fall, then I would not move them now but leave where they are until next spring. That is assuming you have the space. In spring when the ground is soft and the cloves have separated a bit more in the ground you may be able to pull the extras without much trouble, thin your rows so the biggest shoot can grow full sized, and either replant or eat the extras. If they don't pull and separate easily, you can even dig the whole clump, separate roots and replant in spring without any worries about the vagaries of winter. Garlic doesn't seem to object to being moved around at that time of year and will recover from transplant easily enough in springtime.
Separating the plants in spring should not have any impact on whether they form divided bulbs. They will have gone through the winter in the ground, which is what matters afaik.
If you want 100% certain to have a great garlic crop to eat, I would also plant some properly cured and large seed stock this fall. If you can do it, why not?
