Fast metabolism is a very useful trait, for hinkley builds for example it's a must. Chem resistant however is completely useless in PvP, but maybe some newcomers who don't want to have jet negative effect for them this trait can make sense.
To be honest, I kind of don't like your Mule and Handy traits. The first one is far more useless than Fast metabolism (we have strong back and pack rat), the second one reminds me good natured from the previous session, personally I wouldn't use any of them.