non eu getting irish PR whilst living in Northern Ireland

Hi,

My non eu wife and i are living in northen ireland, will it still be possible for a spouse of an irish citizen living on the island of ireland to be able to get irish PR after 3 years even when northern ireland will leaving the eu? my wife now has 5 year pre-settled status in the uk.

Also my wife is hoping to go back home for a few weeks next year would this have any bearing in her future irish PR application?

And final question if my wife wanted to fly from Dublin next year to go back her home as the flights are so much easier from Dublin would she need a visa to fly in and out of Dublin?

Thanks