Most supermarket party pies are dairy-and-meat based, so not vegan. Check the pastry and any egg wash on the label if you want these to work for Paddy too — brands vary.
The easiest win on the kids' table. Buy frozen party pies and mini sausage rolls, and bake straight from frozen per the packet instructions (usually 20–25 minutes at 200°C). Serve with a small bowl of tomato sauce for dipping.
Note — Check the pastry and any egg wash on the label if you want these to work for Paddy too — most are fine, but brands vary.