Can I make the celery salad a night ahead (minus the parsley) and serve at a dinner party? Also: is this better cold or room temp? Thanks!

I agree with Andrea. You could prep the ingredients but I wouldn't dress it until the night of the party.

How about prepping all the ingredients, refrigerating them separately, then combining at the last minute? That would ensure crispness and reduce your workload right before serving. I'd have the salad at room temp so it goes well with the cheese toast.