Two more responses from Africa, courtesy of the BBC:
The resonses I’ve seen from American conservatives, both within and outside the Episcopal Church, are rather cool to the invitation as well. I still think that if this has any big impact, it will be in the UK and especially the Church of England.
Which brings up an interesting question - if congregations from England join the RCC, will they be required to relinquish their buildings and property back to the CoE? After all, many of those properties were originally swiped by the CoE from Rome in the first place.
January 1 - Solemnity of Mary Mother of God
40 days after Easter - Ascension Thurday
August 15 - Assumption of Mary
November 1 - All Saints Day
December 8 - Immaculate Conception
December 25 - Christmas
These would be significant for all Catholics.
Easter is not a Holy Day of Obligation, since it always falls on a Sunday and is already covered.
ETA: Just in case, let me reiterate that the Immaculate Conception refers to the conception of Mary, not Jesus. The Annunciation when Mary assented to carrying Christ, is celebrated March 25, nine months before Christmas.