Spider Carnage rolls a free action with waldo arms and is 2 squares away from target. Can spider Carnage use his "Make 3 close attacks power" for both the free attack and costed attack"? Essentially giving Spider Carnage 6 attacks 1 costed 1 free.

Or even for that matter could whoever is holding waldo arms use actions like flurry or blades claws fangs for the free attack as well as the costed attack.

Answer to both of your questions is no. Spider-Carnage has to use a POWER action to make 3 attacks. The Waldo Arms situationally give the option to use a FREE action that would make a close attack. For Flurry to be used, that FREE action would need to give a CLOSE action in its directions, which in turn would allow for BCF to be used since that power happens during a CLOSE action.