That is a COOL idea, creating a small pond within the borders of your larger pond! Just watch that the lotus doesn't escape its pot, as they're invasive.
I, too, have baby koi, now at least 3 months old, and barely an inch long, and most of them are either ugly "Tobies" or seem to be solid pale pink, gold, or white. Very few have any interesting markings. If they're going to get spots, I wish they'd do it soon, so I can decide which (if any) I'm gonna keep, and which to cull / give away.