You should safely be able to plant in pots a month before your last frost date. It will likely be a couple weeks before the bulbs emerge at the surface. Ideally, plant in deep pots, one to three gallon size, and then you can plant multiple bulbs in the pots for the one season, too. Usually lily bulbs are planted more shallowly in pots because the majority of the roots will be below the bulb, and planting 6 inches deep (from the surface to the base of the bulb) doesn't leave much room for root growth. For some lilies like L. regale and other trumpets, and asiatics, it's not as important since they grow roots along the stalk as it grows above the bulb also. But for orientals (like Kushi Maya and L. auratum), they only grow roots from the base of the bulb.
You could also plant them up right away, keep them in the garage, but don't water them until the later date. Attempt to keep the soil at the moisture level as it comes out of the bag (assuming you are not using the dried compressed potting mix bails). That would be moist so the bulb doesn't loose moisture and may even begin rooting, but not enough water to encourage sprouting.
Theoretically, you can get them growing earlier if you want to be tied to watching the weather all the time so it doesn't get too cold. But I'm guessing with so many, that would be quite laborious.
Of course, the 8-10 blooms per bulb is on a mature plant, not the first or second year.
