What is the ruling on going with campaigns whose tents are in Muzdalifah outside the boundaries of Mina, and does that affect the validity of the Hajj?

Staying overnight in Mina on the eleventh and twelfth nights of Dhul-Hijjah is obligatory according to the majority of scholars, and whoever fails to do so must offer a دم (sacrificial animal). If one does not find a place in Mina, they should camp where the tents end, even if it is in Muzdalifah, due to Allah's saying: (So fear Allah as much as you are able), and His saying: (Allah does not burden a soul beyond its capacity).

The criterion for staying overnight is to spend most of the night in Mina. And if one leaves Mina for the circumambulation of Ifadah (Tawaf al-Ifadah) at the beginning of the night and is unable to return until after Fajr, there is no blame upon them.

Therefore, it is obligatory for a person to search for a place in Mina. If they do not find one, there is no harm in them staying in Muzdalifah, and nothing is required of them, because Allah does not burden a soul beyond its capacity.