Make ahead for a buffet or picnic?

Yes for a picnic next day.
Important:
1) use short pasta
2) use olive oil not butter
3) reserve some of the cooked vegetables before throwing in and mixing the pasta. Add them to the dish the day of the picnic and place on top almost as a garnish. It will give the pasta salad a brighter, fresher and altogether more appetizing aspect.
NB:
Oh and most importantly at the last minute garnish with fresh parsley and mint otherwise the herbs will get old looking.

I after! This would be great to take to a picnic! Yes, I’d refrigerate it overnight and it will definitely be ok to serve it at room temperature. Have fun and enjoy the complements!

I'm no expert, but I took a look at your recipe there and I would definitely take that on a picnic to be served at room temp. There's no dairy or eggs that require urgent refrigeration, so you get a thumbs up from me.