Every modifier of stats will be applyed to the serpent sting with chimera shot. The "problem" is that serpernt sting REMEMBER the "damage modifier" that you have when you apply it.
I mean when you cast SS you have no bonus set procced, so when it procc'd if you dont re-cast SS you will miss the buff on the serpent sting.
Thanks to the fact SS remember the damge modifier, you will need to re-cast SS just once, and not if you lose the buff and gain again.
Numbers:
-Cast SS, dmg: 100
if you gain the 2t10 buff, you get +15% dmg, so dmg: 115 -> here if you dont re cast SS, your chimera will not "update" the numbers and you will continue to do 100 dmg.
If you cast chimera-> SS dmg= 115. After 10s the buff is expired, but SS will continue to do 115 bc it remembers the +15% dmg buff. Here if you cast chimera, chimera will apply ONLY the buff to you ap/agy/ecc, but SS will still remember the dmg modifier buff.
For this is reason: EVER AND NEVER apply SS during viper aspect, coz SS will remember the 50% dmg even if you cast chimera and you must cast SS again for "normal" dmg.