Do friends who celebrate personal birthdays, knowing that this is an innovation (bid‘ah), fall under the scope of the Hadith: "Allah will not accept from him any صرف (compensation) or عدل (justice)"? And is saying "May you be well every year" to them on this day considered participation in the innovation?

The mentioned hadith (definition) specifically applies to whoever innovates in Medina, but some of the Salaf generalized it to include every innovator, as innovation may prevent the acceptance of deeds. Nevertheless, ruling that a specific person is an innovator requires fulfilling the conditions and the absence of impediments. A specific individual is not to be judged as an infidel or a transgressor until the Prophetic proof has been established against them.