1 Question: What is the ruling on saying Salam Alaykum to the disbelievers?
Answer: There is no harm in initiating the salutation, albeit Makrooh (undesirable act) except out of necessity, under whose remit comes Urf. Responding to their Salam should be by uttering [the word] Alayk (with you).sistani.org/15381
2 Question: Is it permissible to send the disbelievers seasonal greetings?
Answer: There is no harm in greeting them on their occasions.sistani.org/26252