any good suggestions on how to perform good jazzy strumming feel on midi chords?
I have been using the slice tool and editing manually but I am looking for a more random/automatic way to handle this. Any suggestions?
sometimes I use Instachord to help me as I like the way they do strumming except they have the same velocity on ever note.
A part answer:
Is there anything in HaLion’s Flex phraser (V6 not SE) that suits?
Spicy Guitar and DSK Dynamic Guitars (both free) have quite usable (and configurable) strums. I used to have a plug-in that had preset patterns; perhaps someone can remind me of the name? Way back last century I used MIDI files, tag line: " for MIDIphiles" 
I wonder if they’re still available?
On the rare occasion I’ve used strums, I’ve preferred to do my own patterns, and have edited velocities, but the 2 free plugins are a place to start.
Cakewalk used to have an add-on from Applied Acoustics called Strum G-2.
https://www.applied-acoustics.com/strum-gs-2/