Quote from itirnitiiProcs no longer proc other procs, so no I don't think the lightning from thunderfury can stun.
However, I am pretty sure they fixed all the weapon procs to benefit from their elemental % damage off gear. So that should work.
Procs do proc other procs. Wreath of Lightning proc does proc the 4pc Tal Rasha lightning meteor. It's what I use with my set to proc that meteor. Not sure if it procs elemental exposure though.. but I hope it does.