Sounds like a real good idea Tad 24 hours can be a little short but as you said you picked a random time frame.
Because I can imagine we don't miss our cats instantly as we assume they are in the cattery to look at them a week later what the cat is they have birthed:-)
But this sounds like a very solid solution!
I can imagine an IM/ Mail or preferable both can be received from cats which are not fully processed to menagerie just so people get a heads up for example with a link to the finalization page.
And this might make it less needed to set the time frame too tight.
Hmm,.. A Menagerie and a Finalize button in the cat which leads to such page might be something, just brainstorming on this
