Not sure what your first one is (possibly Age of Apocalypse?) but the second is Onslaught.
This is where the mysterious Bastion rounds up all the Mutants. Half the X-Men are stuck in space at the time, Wolverine, Cyclops, Jean Grey & Cannonball end up imprisoned and Iceman forms a scratch team to combat the threat.
Has the best J Jonah Jameson appearance outside of ASM in it. Possibly better than the ones inside it too, cracking issue.
Unfortunately shortly after there were some editorial mandated changes, the writers walked and I stopped buying X books for the only time ever.
I keep forgetting how much I love this issue: The X-Men return home to find the mansion gutted, they need to get a bomb out of Scott's chest and the Juggernaut arrives with his lawyer. Maggott and Cecilia Reyes are both great in the issue... so of course they're the characters that get ditched in the subsequent reboot where the Wolverine KO Marrow gets retained.
The book has arrived. Looks nice. I will read it after I finish an absolutely terrible X-Men novel (on page 600 of 688). I am in need of a good X-Men tale and have managed to avoid all HOXPOX spoilers so don't tell me anything!!!
Amazon has 16 (!) Dawn of X trades listed. Is that what follows?