Will Ahri’s effect skins or at least Star Guardian Ahri get new particles for the charm amp?

It's just a balance shift which has nothing to do with animation particles.

I haven't seen anything on the pbe stating particle updates. So not when her changes come out next patch or something. If they do, they will add it when they change her W because they would have to adjust all the skins anyway.

Very unlikely, considering the main reason completely replacing her W was ruled out was that artists weren't available.