Great pond design, Shane! Where is your shelf located? I think I maybe saw it just past your lettuce picture. Good idea, if for nothing else than to get in and out of that deep pond!
Here's another idea for lilies, if a person doesn't have a shelf. I love the floating idea, too, but if you prefer them on the bottom (most lilies I think like to be about 12-24" deep) put something on the bottom to set the lily pot on. Someone else mentioned using one of those stacking shelves that have holes on the sides, are cheap, when turned upside down look like an open garage? I got a set of 3 at Menard for $11. Turn them upside down, get any air bubbles out first, and set your pot on them. You could use anything that is not concrete - buckets, etc. My pond is not 6' deep, though. LOL
Also, I don't care for the plant baskets any longer. I thought they would be great, but what happens is the roots get out of the basket, and then attach to anything and everything around it. That's fine if you never need to take them out, but trust me, you WILL need to remove them probably every spring to separate them so they are not overly crowded. I just tried to move a pot to give the lily more room, and since the basket allowed the roots to escape, and they are attached to the next basket and also the water line going to the bog. Will have to remedy that come springtime. This spring was my second year, and ALL my lilies had multiple tubers. Split them for yourself, give them away, sell them, find new homes for them, and what you keep will be much happier! This time of year, there should be lots of ponders willing to give you lilies. I know I have probably 4 pots of them I would give away if someone wanted to come and get them. LOL But, I'm about 4 hours south of you. Good luck! Looking forward to more pics as I watch this thread.