Why not purchase a small rubber pond liner to fit inside the box? That would have filled the space easily without the work.
None of the plants that you mentioned are really pond plants, they are houseplants in the broad use of the word. With the exception of course of pond lilies.
Water lilies require not only good sunlight to bloom reliably but warmth as well. What is your plan for keeping the water warm enough. And water lilies are not floating plants. They are anchored in pond soil or the muck on the bottom of the pond.
I had an outdoor pond on Long Island for over 35 years. I grew pond plants, lilies, iris, Cardinal flower, water lettuce, water hyacinth. But I am a little unsure of your goal.
My Tropical water lilies went dormant when the water in the pond remained below 70 degrees F. I overwintered them in my greenhouse where they barely survived due to 58-60 degrees at night.
Native lilies flowered in cooler water, 65-70 degrees F. but required great light. I had to keep things pruned around the pond in order to keep the sun as strong as possible and even at that they were never prolific bloomers.
