You don’t think the Catholics and the Irish government would take care of that themselves? Seriously, how long would the “protestant paramilitaries” last in a united Ireland? How long did the IRA really last in Ireland after the civil war? Not very long - and the Protestants would have nowhere to go, nowhere to hide, nowhere to get arms or equipment, etc.
I don’t think the protestant paramilitaries will last very long, but when a group is cornered they will either fight or roll over. The paramilitaries have shown that they will fight; and the violence that they have inflicted in the past is greater than anything the IRA ever did, albeit they had police and British military backing and that won’t exist to the same degree this next time around.