In the event they actually exit I'd expect Scotland to poll and achieve independence and the Common Travel Area to be administered on an all island basis. Dublin gets the chance to bring some London multinationals over before Scotland post independence competes with us as the only native EU English speakers. We will have about a 3 year head start though.
Nothing really happened today. The markets will recover but in the long term trade between Ireland and Britain will be affected if there is a depreciation in the pound post actual exit as English markets will not be as eager to buy Irish goods at a higher price. Trade tarrifs will also apply.
The north is in limbo though, it heavily depends upon the European subsidies for the agri food sector and it receives monies from England that English nationalists will want to pull back on. In effect the English don't want it, and we can't afford it due to its lack of a private sector.
The alternative is Brexit 2 but the English might not tolerate that as easy as we would.