Sorry, what???? The IRA cannot annex Ulster or anything else because it is not a country or state. Therefore whether it has the right, doesn't enter into it. The Irish Republic, on the other hand, does have that right if at some future date the inhabitants of Northern Ireland (including Ulster) decide that they wish to leave the United Kingdom. This is written into UK law, which obliges the Secretary of State to make an Order in Council enabling a border poll “if at any time it appears likely to him that a majority of those voting would express a wish that Northern Ireland should cease to be part of the United Kingdom and form part of a united Ireland”.Ulster had been a part of Ireland for several centuries ,but that does not give the IRA the right to annex Ulster .
Back to the subject of the thread. James, I feel you might be somewhat overstating Polish military might. In 1937 there was only one mechanized brigade and that only from the middle of the year at best. Also, without sorting out the Polish Army's ammo supply issues - particularly artillery ammo, it would not be able to function for long.
On another line, I don't see any sort of Intermarum functioning or even coming into being without Czechoslovakia. But that's just me.