does cyberlimb quickness effect reaction, i can't seem to find the rule on this.

oh it may be good to note that the character concept has 4 cyberlimbs.

Basically, yes. I don't have M&M handy, but the rules are there.

M&M p 34. use average quickness of all limbs (natural and cyber) to determine combat pool, reaction and initiative, so ((arm + arm + leg + leg) / 4) for the average.

would it also affect the cost of skills? i guess i'm asking if cyberlimb attributes are considered "natural"?

Bioware is defined in M&M as a natural attribute increase - cyberware, either muscle replacement or cyberarm limb enhancement is not natural, so it not effect chargen/karma costs for skills