I'm in Michigan and I didn't have trouble with survival of hardy waterlilies. I planted mine in a plastic tub, placed it in shallow water and as it emerged I put the tub deeper. As the stems grew to the top of the water I moved the tub deeper yet. Once the tub was a few feet deep and the rhizome wasn't in any danger of freezing in the winter ice I left it and the waterlily always came back. I was warned not to plant my waterlily in my pond bottom because it could become invasive. I guess it depends on the type of waterlily you choose.

My problem was turtles and geese cutting the stems. I put a chicken wire cage around the tub that came up to the water line. This worked pretty good for getting them established but the leaves and stems grew further out than the cage and was regularly cut up by the wildlife. I made the cage wider but it didn't help much. I had it several years and only saw it bloom once thanks to long necked geese and turtles. When the chicken wire rotted away the rhizome was destroyed or it died, not sure really.

I liked my waterlily but it was too much of a battle keeping it intact. Since you have ordered a bunch of them you might have better luck keeping some of them going.

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