The underside of the leaf has an unmistakeable mealy or grainy look. Yes, they're edible (I believe both raw in salads and as a cooked vegetable).

Man, I love this site. I get answers to questions I didn't even know I had! I have one of those in an area I haven't tamed yet. Thanks for identifying it, now I won't pull it out. Thanks!

the biggest problems with collections like this ... is two fold ... first... the pot has no drainage ... so it wont make a mess at the funeral home ... this can lead to nightmare watering problems ... especially ... secondly.. if two of the plants have diverse watering needs ... e.g. many ferns do not like swampy soil ... but the others might ... once you get your IDs ... you should head to the houseplant forum ... and ask them how to break up this pot .... into 3 different pots ... and that way.. you will have 3 remembrance plants ... or all three into a bigger pot with good media.. and drainage ... theres a lot of plants in that rather small pot ... think of it this way ... this plant came from a florist ... it was made up.. for high impact and wow ... a nursery .. where they sell houseplants.. might have done it much differently .... AND THATS WHAT YOU HAVE TO FIGURE OUT.;. FOR LONG TERM SUCCESS ken

"The cells of the Dieffenbachia plant contain needle-shaped calcium oxalate crystals called raphides. If a leaf is chewed, these crystals can cause a temporary burning sensation and erythema. In rare cases, edema of tissues exposed to the plant has been reported. Mastication and ingestion generally result in only mild symptoms.[11]" "Many plants accumulate calcium oxalate as it has been reported in more than 1000 different genera of plants.[2] ... It is also found in rhubarb (in large quantities in the leaves), cinnamon, turmeric and in species of Oxalis, Araceae, Arum Italicum, taro, kiwifruit, tea leaves, ... and in spinach in varying amounts. ✔ ✔