Need better closeups of the plant's leaves and bark. May be Magnolia grandiflora.

You can google indoor water gardens and get some ideas. I would stick to native bog/marginal plants like pitcher plants, ferns, cattails, Louisiana irises (or other types), maybe native violets, rather than African. You can also have a few water lilies in there. Good luck! It sounds like a fun project and a progressive school! A few "tropical" plants wouldn't look too bad, I wouldn't think. Like some papyrus, cannas, elephant ears or philodendrons. Just for filler in the back part. You need some height. You could also put some bamboos or sedge in some pots. HW Here is a link that might be useful: here's a schoolyard pond for indoor or outdoor

You can grow them in miracle grow potting mix (works well for me) but since it's a project I would put them in the pots with rocks and set the pots in bowls of water so they are constantly moist. You can if you want just grow them in vases full of water, they will be OK. (I have some in a fish tank) keep us updated and pictures are really helpful. :)

I agree with you garystpaul about seeds being different then; if they are long black floss like with bump, then it is chervil. I grow it for my kitchen garden; herbs mainly used for fish and soups fresh, when I was growing up in France with my Great Aunt. Must start from seed every year in here in Seattle, WA Z7 & Z8 as an annual herbs -- it doesn't seed itself; but I don't see a picture of the seed, only the starts -- pictured above. Foliage to my chervil is allot more lacy than pics above; I collect my seeds every year from some that I let go to seed, annual herbs I've used for almost 50 years (very mild licorice flavoring).