love bug: sorry to hear of the dying cats!
dzyg: very cool thing to enlighten the youngins early to take care of nature!
An update on my situation: one plant looks absolutely pathetic. It got eaten partially and is now looking horrid, and I don't think it's because of the eating. A couple of photos are enclosed below. Both milkweed plants (the other does not look the same as the photo, it appears fine) have been abandoned, and no cats remain. I've managed to spot 3 (2 somewhere on the cage, and one hanging on the pot's rim. Hopefully they've gone to pupate, I guess I'll see soon enough.
Unfortunately, I think that this plant's got some sort of systemic problem. As mentioned earlier (in this thread?) I've been to mom's and obtained 7 more, but now I'm short one plant. Thankfully I went and bought two more milkweeds before stopping at mom's...but they're young and surely won't last with 3 cats on each. One of them is an all yellow milkweed flower.