So I moved and have to wait about a week to get my internet hooked up, figured I could play campaign and get the skulls/Intel untill then. I know achievements don’t unlock while your offline but if I do this now will they unlock when I go online?
Yes, they should as long as you’ve met the requirements for the achievement. Say you complete the game solo on Legendary and collect all skulls and intel, you’ll unlock the relevant achievements all at once a few minutes after your Xbox connects to Live. Your save file needs to be synced up once you connect which is why the achievements won’t necessarily unlock instantly. This will work for multiple games too, so feel free to jump around and play whatever you like!