Instead of necroing a 15 year old thread that has nothing to do with your question you could have made a new thread about this topic.
Precomps: you can either duplicate or (usually) route the same output from a node tree to different places.
Expressions: there’s a bunch of them in Fusion.
That said: if you have everything you need in AE then why would you need to use something else, unless you need some special toolset that can only be found in certain piece of software?
If I needed to comp a lot of shots from render passes, then I’d be mostly in Fusion or Nuke. That can be a pain with layers IMO.