Quote: They'll be like a day old when I get them. Yea, I know. So, I'm gonna give it a mirror and a stuffed animal.
Well, you see, my feed store is selling chicks. I pick them up at the store.

The BO will be alright for a week until the EE gets here right?
Getting them 2 weeks apart in age is the maximum you should go, according to the chicken guy at my feed store. I introduced 3 chicks to a group of 9 that were two weeks older, and they did fine. Your 2 week old Buff Orp will be feathering and so much more active than the day old Barred Rock, but should be okay. Just keep an eye on the youngest each time to make sure they get enough food and water, and pick really active, alert chicks from the feed store brooder. Check for clear eyes and make sure the vent is clean (no poopy butts, aka pastey butt). A chick that peeps loudly, walks well, and is interested in eating is probably healthy and will do well for you. (But then when they suddenly fall asleep on their faces, don't be alarmed, it's normal!)
Early congratulations! I think you and your mom will love them. Now all you have to do is build the coop!
Two months to go! Hope you share pics!