It would be better, if we knew where you looked for the promotion. If its been given out by ASUS, then you can expect a ROG wired mouse and headset. If you saw it somewhere else, then it totally depends on the seller. Most probably, they'll tell you what brand and model of the freebies you get. I'm most probably guessing that you found this on ASUS because I remember them running the same kind of promotion before.
And for your second question, no you'll get DIFFERENT boxes for the notebook, the backpack, headset and mouse. They MAY be shipped together though, so in the end, all items might be in one box. Again, you have to check with the seller on this as some sellers ship freebies after the original item had shipped, or sometimes if any of the freebies goes out on stock then they ship those separately later.