The only call that I'm not understanding is the one to ALP. The other calls can be easily explained, IMO. Yeah, it was the middle of the night, but she knew SN was awake because she had just seen him at the apartment, and
the call from PP likely was checking her order for Whataburger. The multiple calls to HF don't strike me as strange in the least. When I was younger and fighting with a boyfriend, I, on a few occasions (she admits, embarrassedly) inundated his phone with calls simply because I was SO angry and hurt by him, that I wanted to annoy him (childish, yes, but people are usually fairly immature, at least in some ways, during their 20s). Not saying this is what happened between Christina and HF, but it's as valid of a speculation as any of the others, IMO.