@ Gerald, I think there may have been a few things that you misinterpretered, making the episode somewhat lacking for you.
'-So why did Jack's girlfriend feel the need to get Nolan punched in the gut for doing the family a solid? (This point kind of leads to another problem I had with this episode....why introduce questions like these that revolve around characters we'll likely never see again?)'
I'm not sure if others agree with me, but I read your review prior to watching the episode so my expectations of this particular scene were that she 'arranged' to have him beaten up.
She didn't kiss him to get him punched, earlier in the episode she talks about having no money and being stuck in Montag, when she listen's into Nolan and Porter Senior's conversation, she overhears that Nolan is a multi billionaire. She then decides that he is a way out for her, emphasised when she says 'Me and Jack don't want the same things anymore'. It's basically showing you why Jack and Nolan weren't overly friendly when the season started and what happened to his girlfriend. Hope that helps!
As for the episode itself, I actually think it was done really well, the whole season is built on flashbacks and this was needed to show her transition from not wanting to know, to feeling the grief and guilt over Roger's death. It portrayed her innocence and the moment that she decided enough was enough and that they needed to pay. I think it was handled very well.