Does entering the multiplayer lobby and opening the starter pack add all the gear from that pack to your campaign inventory? Because I went from a nearly empty inventory to having tons of stuff, a lot of it way over my level, and the only thing I've done since last night (when it was empty) and now (when it became full) is look around the multiplayer menu. I was under the impression that multiplayer starter gear would be on its own somehow.
Yeah, multiplayer items and single player items share the same inventory and can be used interchangeably. Meaning you can earn items for multiplayer by playing the campaign and can earn items for campaign by playing multiplayer.