Old Glory has Irish armored cavalry in their War of the Roses range. For un armored cavalry I use Old Glory Pict cavalry from one of their dark ages ranges.
Crusader Scottish cavalry from dark ages range will also work.
Some of the poses from Footsore Dark Age Irish would work, but a lot of them have "Arthurian" period helmets or armor. Same can be said for Gripping Beast Irish cavalry. Check those companies armored and unarmored cavalry. Because they sell them in blister packs not all models will work.
Redoubt makes few poses of Irish cavalry specifically for your period, check their renaissance range. Not sure of their quality as I never seen them in person.
For buildings – check Scottish ranges from dark ages. I have resin buildings from, I believe, Architectural Heritage. They used to be sold by Old Glory. I am not 100% sure that they good for Irish buildings, but that is what I use.
If you want I can send you photos of all I have painted so far. buildings and Old glory cavalry and you can decide by yourself.