This is a team match 2 vs 2. now this team was decided because they are brothers or close relations to that. so for the first part.
Cyclops and Havok
Scott and Alex have never really seen EYE to eye. (HA!) but we know their powers negate each others but now work together. as they face....
Skeletor and King Randor.
Randor has had nothing but love for his brother Keldor before he was betrayed, and now turned to Skeletor overlord of evil. the two work together for once in their life to face off the summers boys. Though randor has no powers to call his own he has impressive battle skills and great tactical knowledge.
Abandoned and partially destroyed Manhattan island. (go with I am legend version), Lots of rain as thick dark clouds bring down tons of rain, thunder and lightning.
Either by kill or complete knock out.