I'd say
1) She was definitely meeting someone, however briefly. So anything from a thank you to a bnb host for last-minute (off the books?) accommodations, a drive by for a "few drinks" with someone at his/her/their home on her way to her final destination, or supplies for a beer drinker already at (or coming to) wherever she planned to stay. I lean towards the latter, unless the host was someone she knew specifically liked that beer. I don't read too much into it being Canadian, college kids don't head to Russia for Stoli Razz. It's also entirely possible she bought it close to when she crashed, and it was the only 12-pack available if she were going for something cold. It would be readily available in NE towards Canada. But if she wanted it cold-ish, that puts her destination closer.
2) It doesn't necessarily follow, but I'd think whoever it was for drinks as much as she did. In other words, a 12-pack might be for the first night-into-day until they could go to another liquor store. Or it was intended as a 1-night rager, at least for the beer drinker's involvement. Alcoholics make sure there is always enough, but this also smacks of not wanting to be out at a bar, restaurant, etc. Likely because she was intending to get hammered and didn't want to drive. So if she was drinking in the car, I'd chalk that up to she's an alcoholic and secondly maybe she wasn't all that far from where she was headed and wanted a buzz on arrival.
3) This is literally a proactive beer run and maybe she did know (or was told) what beer to get. So, who did she know that drank LaBatts? Julie (or anyone else) isn't going to say and catch a defamation or slander case. IMO, redacting the beer screams LE knows, or has the keys to knowing, the most importance piece - there might be a 2nd person in the original plans. Coupled with a phone tap, it sounds like finding the evidential 'clincher' is the issue, not necessarily that they don't know who/what/how.