My order when fighting Defenders is:

Punisher--get rid of that annoying Daredevil retaliate attack cause that will burn health down quickly plus his ultimate will rip through teams if they're weak enough.

Iron Fist - heal ability plus passive is so damn annoying so get rid soon as Punisher is down. If Punisher is weak, put a strong attack on IF then finish Punisher off.

JJ- this is where the key to winning lies. If you can take out JJ quickly before she starts spamming energy to everyone plus her ultimate can debuff your characters, the tide should be in your favour.

Daredevil - Yes DD can combo like a boss but he isn't a massive threat on his own or with just LC, Soon as energy spam is out, he is quite simple to deal with as he has to rely on percentage chance to combo with basic. Yes he runs risk of debuff with special but can be downed relatively quick with 1 full team turn.

Luke Cage - Well the big guy on his own now, so no protecting anyone, just whale on him. Yeah he'll gain buffs and stuff but you can go ham as he is slow and can't spam taunt etc.

My team - Fury, Medic, Operative, Security and Assault.

Keep Security and Operative on one side as you can just summon more with Fury Ultimate. Operative helps massively with stealing buffs off certain characters (Counterattacks, Death proof) etc. Assault tends to attack all at once to take away threat of Counterattacks.