Do you know which species/variety of lavender you have? If it's Lavandula angustifolia or Lavandula x intermedia (two most common types), it should be hardy enough to be left outdoors. If it's in a large container with very well draining soil, it should be fine.

I would go ahead and plant the daffodils now. Don't wait until December. The ideal planting time for this area is late September. Daffodil bulbs grow most of their roots and establish themselves in fall and early winter. I think the advice you read about keeping them in the frig was likely related to forcing the bulbs for indoor display.

Thanks so much Brandon.Appreciate your help. Jen