Reply to New Setup, PLEASE HELP!!!

Hi Everyone!!! After a couple weeks believeing on updating my setup, I believe I have an possible idea of it, but some things are not 100% clear. Could you help me?

1. For Traktor Pro 2, which one is better: MIDI Fighter Classic or Novation Launchpad?
2. Should I get a mixer? In case I should, I thought about the Behringer VMX200, what do you believe about it? Which version is better, with or without USB?
3. Is the Audio 2 DJ Soundcard from Native Instruments good enough for 2-Channel Mixing?
4. Is it logical to buy a Novation Nocturn, even if I get a mixer or I use the Instant Gratification Mapping?

I really need to know this as soon as I can, so please I wait for some answers!! Thank you (and sorry for my english xD)!!!