3 is easiest - wracks are Elites in the dark eldar codex with no way to make them troops, but they are troops in the haemonculi covens supplement. We've got Urien, Lelith and Drazhar, everyone else is gone.
2 - bloodbrides are an upgrade to wyches that makes them elites, you can have as many as you can have elites.
1 - I dunno about army builder and their formatting, but wyches have 1A on the profile, but come with pistol and knife, so it's still basic 2A. Just the same as the previous codex.
I advise you to have a listen to Splintermind by a couple of the kings of TDC, they're doing a really good breakdown of the changes in the new Dex. Start from episode 2 for post-release podcasts.
Be prepared to lose interest in your wyches as a serious battlefield force.