An inheritance is potentially liable to tax, subject to reliefs and exemptions, if the disponer (deceased) is resident or ordinarily resident in Ireland. Property situated in Ireland is liable to inheritance tax irrespective of the residence status of the deceased.
So it doesn't matter where your beneficiaries reside if you are Irish resident at the time of your death then they may have to pay tax on your estate.
Now, whilst we have had some success in post death planning in specific instances, there isn't much that your family can do after you have died unless your Will includes specific provisions to allow them to take advantage of any post death planning.
If your family takes tax advice after your death it will be to work out how much tax they owe.
However, if you take advice now there should be substantial tax planning opportunities.
Whether or not you choose to enact any planning is a very personal choice in my experience.
A final thought from the UK on the subject " inheritance tax is a voluntary tax paid by those who distrust their heirs more than they dislike Revenue"