So I'm not sure how many people actually want/need/care about this or haven't already found it, but here goes. I found a strategy on gamefaqs for taking down these guys that basically works every time once you get the hang of it, and thank you PS4 share for the video capture.
https://www.dropbox.com/s/pljj0lfclq4oe … r.mp3?dl=1
To summarize, simply pick Rashid, and use heavy eagle spike repeatedly, jump back if it's blocked. If it hits, just do a backdash and do another eagle spike.
The second fight, I kinda cornered myself, which is mildly dangerous to do with these things since their damage output is so high if they get you in a long combo. I think I kinda lucked out on that one.
Anyway, hopefully someone besides me gets some use out of this, and can get that sweet sweet 18000 FM reward for winning all 3 fights before tomorrow night.