Luke Cage and Shang Chi? No thanks. Part of the appeal of Heroes for Hire is seeing Power Man and Iron Fist working together. Those two are like the buddy movies of comics. That type of dynamic hasn't been seen in any comic book movie yet as a major premise. Those two were always more interesting together anyway than on their own. As separate movies, each could easily go the way of Elektra or Ghost Rider.
Since Shane Black has worked on Lethal Weapon and on Iron Man 3, he could be a potential director for Heroes for Hire.
I think the way to go about it would be to introduce each seperately via SHIELD. Both Luke Cage and Iron Fist could have a focus episode and then that would open up the possibility of spinning off both into their own Heroes for Hire TV show or film.