I lucked out today in getting my local petco a biologist and fish expert. We were able to talk through several things. He doesn't know as much about plants, but our discussion has motivated him to go learn more.
Just FYI, Peace Lilies (Spathiphyllum) are not lilies, therefore are not toxic to cats. The worst to expect would be stomach upset.
<<is a veterinarian
I have seen first hand a cat dying after ingesting Peace Lily. I may not be a veterinarian, but I do know my plants, even if I am just a high school student. Not to mention that even if in some cases, Peace Lily may not kill your pet, it is not recommended to be kept near them, as every animal is different and will be affected differently, obviously. Not to mention information given out by major, and trusted, at that, organizations. ASPCA | Peace Lily
Ok so I have just purchased: Mondo grass, java moss ball, java fern, cryptocoryne, and a peacock fern. I want to get some Anubias down the line I think.
Mondo grass is a non-aquatic plant. I know that it's sold as an aquatic plant in some pet stores, and I , too, purchased it believing it would be fine. About a month after I planted it, someone told me that it was non-aquatic, and sure enough, the googler confirmed that information!
About two weeks after that, I had found a replacement plant and removed the mondo grass. About half of the plants had issues with the roots (separating from the stems, stunted growth, etc) and even though I replanted them in potting soil, they have not done well.