UE4 is a gem to work with. For what you're describing, do this;
- Create base 3D character using 3DS max/Maya/Blender
- Add blendshapes to the face and body for major archetypes
- Tweak blendshapes in UE4 through blueprint
I don't know how you're doing motion capture, but I've found the Kinect does fairly high-quality captures for my purposes. It does have a downside in being one viewpoint, as opposed to full-surround captures.
I recommend using a number of basic animations and blending through them - 'TalkGeneral, TalkEmotive, TalkEmphatic' moving the head in looped motions. Use UE4's AI controllers to just set up the characters to walk around between full-captured animations. Have blended full-body motions too, like 'IdleSassy, IdleWorried, IdleBored' etc.
Using these methods you can save a lot of time, but it requires a bit of groundwork.
As far as lip-sync goes, it's up to you whether you want to have a generic mouth movement, a programmatic approach or custom-made animations for each sentence (in order of ascending difficulty). Blendshapes can be used for facial animations as well, for a very quick approach - that way you just specify timelines of phenotypes; 'HH-Eh-Loh-FF-RR-EH-NN-DH'. You just cycle through each facial blendshape.
The same thing can be done for emotions on the face. Most of what you want can be done through blendshapes and timelines.
Hope this helps!
EDIT: I'm very experienced with UE4. Been using it for years on a variety of projects - if you want any advice there are plenty of tutorials out there and I should have time for a bit of help if you need it. My policy has always been 'highest quality, lowest effort', if that's compatible!
[—Connor M]
