Can you please show where those are part of the Catholic faith, as referenced in the Catechism of the Catholic Church?
In any case, don't eggs symbolize the cycle of life and the hope for a future?
The Catechism is silent on the subject, and irrelevant to the conversation. The question on the table is why the date of Pesach was changed, and whether the decision on the dating had pagan overtones--possibly because of an attempt to co-opt the pagan culture by the Ekklesia. We would not expect the Catechism, which deals with current Catholic theology, not the historical debates, to speak on this subject, so one wonders why you're referencing it.