And the U stands for Unionist. Perhaps you are not old enough to remember the GFA negotiations, the Ceasefires and what happened before them. The UUP was the dominant unionist party in NI. Now it is not. The DUP is currently the dominant unionist party in NI. JA allows for a gradual change rather than uncertainty. The abrupt change will be the Nationalist majority in the next few years. This will isolate the unionists and possibly destabilise the North. JA would provide an element of stability in the transition to an United Ireland.Which voters? Which voters for the DUP and the UUP are going to stick around? I've even bolded the key letter in the acronyms for you.
That can be changed.All the major parties are united on the UK not being disrupted in exactly the way you're describing.
You don't seem to be sure about a lot of things.I'm not sure you could point NI out on a map.