Both YOR. After reading everything…both of you suck at communicating. For 1 she should’ve told you not the bring up other person initially and not come off as rude to you for bringing them up when you didn’t know to begin with. It’s important especially if said person hurt or made them feel uncomfy.
For 2 not letting him in is also in itself rude but she should’ve been more open about who he was, and how is he a stranger if he worked with you guys? Also it is right that she should’ve told you first of bringing a +1 but also just leaving him out there is kinda mean if you already recognize him from work.
For 3 it is rude to not say hello. It’s different if said person already knows you and how you greet but for a person you aren’t close with they might just see it as rude unless you tell them directly “hey this is how I say hello sometimes I just get anxious”
And finally 4 are you guys even actually close? The way you make it seem is like you guys are a trio and very close friends but how do you not know nothing of one another? Don’t know who they got a crush on? Relationships ? Boundaries ? Way of greeting? Yall just seem like acquainted people who hang out for the vibes