Great to have the Irish perspective, Nuts, and on the issue of uniting Ireland, if the people of the North voted to leave the UK tomorrow, I personally would give it 100% backing (as I believe most people would on mainland UK). There doesn't seem to be an appetite for that at the moment, so far as I can tell, taking all the communities in NI into account. I may be wrong, but that's my perspective from a distance.
As to Brexit, of course, the Irish Government has every right to argue the case for its country's best interests. But recently, we have seen the Mr Varadkar and Phil Hogan, Ireland's EU minister, calling for the UK to remain in the Single Market and Customs Union which, while it would solve the Irish border problem, is encroaching into matters of UK governance. There's a strong feeling the UK, among Leavers anyway, that staying in the Single Market and the Customs Union would mean the UK isn't really leaving the EU, will be subject to all its rules, be billed annually for many billion £'s and yet have it's voice taken away. It won't run imho.
As I say, the UK has to work with the EU, particularly Ireland, to find a Third Way in order to keep a soft border and yet allow NI to be treated as the rest of the UK unless and until there is a strong movement to leave. On a personal note, hope all is good with you over in the Emerald Isle, Nuts - leaving aside border issues(!)