I don't buy Jessica Jones and Luke Cage joining a superhero team
They're just two average joes who had special abilities forced upon them, and unlike Daredevil they don't enjoy the superhero life. In the long-term they crave an ordinary existence and just want to be left alone.
Any action they've both taken up to this point has been driven by a combination of desire for revenge and basic human decency rather than a genuine desire to tear down corruption and clean up the streets. I can't see why they'd want to team up with two costume wearing weirdos to fight crime on a regular basis.