How far ahead can I bake puff pastry?
Puff pastry itself holds fine a couple days (and the raw dough can be kept frozen months!); it's normally very dry so there's very little difference between baked fresh and "old". As long as you don't burn it and don't make it soggy when reheating, the pastry will be fine. OTOH if you keep it on heat, it will start getting too dry and unpleasant in some 3 hours or so.

The meat stuffing is another thing you should worry about. 4h on very modest heat will dry it up badly.

Just bake everything ahead of time, leave in the open in room temperature or even refrigerate and reheat every batch before serving.