Normally I like Whedon stuff but I think you could have varied the team a little bit and maybe thrown in Zoe or Wash from Firefly. Maybe Capt. Awesome or Dr. Horrible. Or even branched out into Whedon byproducts like Felicia Day's Guild. But 6 characters from Buffy/Angel doesn't really make a fun team I think.
You probably should have mixed and matched the Mars Investigations Team/Whedon's Warriors and then branched out a little.