As a DM, NPC companions are great if you want a direct line to your party members' ears so you can inject things like "hunches" and "common sense" and "no, that will get you all arrested/killed" into the conversation without being too obvious. Transcript:
Twilight Sparkle: Wellllllll… Umm… Spike, what do you think? Spike: Why the heck are you asking me? Applejack: She's not-so-subtly asking for the patented ol' "DM nudge in the right direction." Spike: Oh. Well, I mean, where would you start? Any one of these would be apocalyptic mayhem on its own. Except maybe the popcorn. I dunno. If this is really happening everywhere, I think this might be bigger than Ponyville. Bigger than us. Twilight Sparkle: That's your advice?! Just give up and leave?? Spike: I'm saying maybe this won't stop until we find the source. Rarity: I, for one, cannot in good conscience leave these ponies to stink in rotten milk puddles. Let's see what can be done before we head out. Twilight Sparkle: My thoughts… more or less exactly. Spike: Glad I could help…?