1) この際, not その, so "this time" not "that". Sounds to me like, just as in the next paragraph, the speaker is trying to convince the listener that "they aren't bad people, so this time it's fine no?"
2) It hasn't changed since the beginning of the paragraph: it's still あいつら.
3) 割り切り = making a decision, 早い = fast. He's annoyed at how quickly (recklessly) the decision was made to work together with the more or less questionable あいつら - his small admission (それもそうね) was already enough for them to act as though he had no further complaints and seal the deal.