Sometimes animals just don't have that "mothering" instinct. I've seen it in dogs and cats before. They'll have the babies and then want NOTHING to do with them. They just abandon them. If the kittens were all in the closet but spread out it's possible they were squirming around trying to find momma and that's how they got separated.
Personally I would not breed her again because chances are she still will not want to take care of the babies. Hand rearing kittens is very tough - much tougher than puppies - and does not always have a good outcome.
If you do decide to breed her again you're going to want to keep her isolated when she gets close to her due date. Either put her in a bedroom with everything she needs or at a minimum block off access to bedrooms & closets so she can't have the babies where you won't find them.
Dallas, TX USA
Diesel - snow Bengal born 09/01/2013 adopted Feb 2014
Tuck, Chloe, Buddy, Lewis & Tia - rescue kitties
Clyde, Bleu & Coal - Great Danes