Is it permissible for a Muslim woman to visit her Christian relatives on their holidays with the intention of maintaining kinship ties and avoiding estrangement, provided she does not participate in their religious rituals?

It is permissible to maintain kinship ties with non-Muslim relatives, visit them, and treat them kindly. However, it is not permissible to visit them during their Christmas celebrations, as this involves condoning their falsehood, increasing their numbers, and congratulating them. This is one of the forbidden rituals of disbelief by scholarly consensus, and it also falls under the avoidance of false witness, with which Allah described the servants of the Most Gracious. Enduring their reaction is better than committing what is forbidden, while striving to invite them to Islam.