Disclaimer: I haven't tested any of these to see how good they are, or to check how well we can make them work like we want.
I'd support 1. I like that idea.
2 I'm so-so about. If the reason why we got rid of MobCatcher is because it got old, then sure. If there was another reason, then no. I forget which one applies.
3 looks, okay. I was working on something that adds some similar features. The general idea is alright, but this approach seems a bit over-the-top, in my opinion.
4 I'm personally against. I never really liked mcmmo, as in my opinion it doesn't really fit in with the server too well. If you all want it, I'll add it, but my opinion is no. Sorry