Things happening way earlier in this timeline was already addressed as a plot point (like Sinisters experimentation with Chimeras is supposed to be way in the future but he’s already working on it now.
Re this issue, your personal mileage will vary but I enjoyed this one cause it was a playground scrap as you say. The mutants were not expecting what they encountered, and weren’t even trying all that hard. Nice change of pace for me from people who just hate mutants because. These guys specifically hate what the mutants have done with Krakoa and the impact it has on their own plans. Makes them not such clear cut bad guys and I’m curious how their later issues pan out.
And I’m a Scott/Emma fan so I really liked their interaction here. I don’t much care who Jean is with long as it’s not Logan (just please no let that die). I wonder if Emma is the one person Scott loves that referenced in the previous issue.