The adult shrimp were purchased off an eBay seller discussed here. I did place some in the fridge overnight to test cold hardiness and all survived.
Unfortunately, due to their color, 2 minutes after releasing them they were never seen again. I guess I need to take like a pool skimmer with me next time to try and catch some. I hope they survived as there is minimal predation and decent cover. Ideally I would get them breeding so I can establish them into the big pond.
I will also transplant some of the scuds to the big pond in a secluded area.