Possibly the ones that germinated did not have seed dormancy while the others did and two weeks damp chilling was not enough for them. At this point I would either put the ungerminated ones back in the fridge damp for 4-6 weeks and then try again, OR take them out of the vermiculite and drop them into a solution of 1:9 household strength hydrogen peroxide to water (that's assuming the H2O2 there is already diluted to 3%) until they germinate OR leave them where they are and wait it out. I would not put them back in the fridge at this stage and wait until spring.
If you try the peroxide soak it should be at room temperature and out of the sun.
