A very interesting take on crossing over an existing IP with a Brand new one but it works very well.
Yang as Reaper is an interesting choice. Very often I've seen Ruby being referred to as a "reaper" given her use of the Scythe weapon but I agree ultimately wiith you choice here as the personality would not fit the character. Yang, especially post volume 3, would probably be more prone to sullen/vengeful/angry lashing out behavior and this fits the presentation we've seen of reaper in Overwatch promos. I particularly like the matching glow you gave to her exposed eye and the LEDs embedded in her armor.
For Ruby as Widowmaker that's another interesting choice. But granted, they both use sniper rifles so I kinda see why you picked them as well as their motivation for sort of "going solo" at least as far as Ruby's singular desire to be a huntress vs Widowmaker's desire to never be betrayed.
I noticed a bit heavy use of blurring on the piece here. I see that it appears they're leaping out of something since they appear very high up in the skyline, but I feel it could be toned down just a jot with the edges of the pic.
Otherwise the color and tone work very nice. Got a definite Cyber-Punk Neo-Tokyo vibe going on here and the idea of Ruby and Yang working as cyber-hunters working in some dystopian urban future sounds badass as hell.
Nice job again, looking forward to more.