Questions about Rigging/Animation in Blender and UE4

So I’ve started working on an FPS in UE4 and I’ve got a fair few assets for animations (mainly the free assets that are on offer) but I’m a little stumped on bringing in my own models into the game and using the pre-existing rigs in the engine.
So my questions are:

  • Is it possible to use the UE4 rigs for my models without much issues, especially around different vertex groups. (Like making sure moving the head doesn’t manipulate the chest, ect.)
  • Some of my models have triple jointed legs, will that mean making my own rig? And is it possible to apply animations to that rig or will I need to start from scratch?
  • Can I import rigs from UE4 into Blender and use them for animations?
  • Have some custom animations in mind, can I use the UE4 rigs for this? Or, again, should I consider doing animations from scratch?

I’m not to concerned about creating my own animations and rigs for some of my assets, but I’m just wondering if there’s ways to streamline the process.