What did he/she do in August?: Started out by asking Acumen about GIR, then lurked when Rolo showed up, asking Lelouch how they were going to handle him. Then Euphie got Morgan. She and Lelouch plotted to kill it. She attended Suzaku's sex ed class for moral support, and she also trolled Yuuri and Uther, which was fun.
When Euphie wanted to put up a playground, she popped up to ask why Euphie wants to change everything around. She gave Saber a hard time about eating all the pizza, and then trolled Naoya and Lelouch's chess match.
She met Gambit and tried to meet XI!Lelouch, and said hello to Kagyua. She avoided the visiting Kallen because Lelouch told her to, and she got revenge by trolling Nunnally and Kaguya when the Old Spice Man appeared. Morgan and Beagle played in the kitchen during Lelouch's party. She also quizzed Peony on fonons.
Then there was Nunnally Walkies Day! She talked a little with Nunnally about it, and offered to take care of Nimue. Then she talked to Lelouch about how it went during his Angelic Layer/Chess Match party, where she also talked to Sebastian.
Any plans for him/her?:
She's leaving home, bye-bye... Sort of. Casa de vi Britannia is getting crowded, and she's going to deal with that by finding a place of her own for a while. Probably across the street or down the block in Sector 4's "exceptionally unsafe" apartment building. XD
Back to school season! Does (or did) your character get a higher education, or drop out? What do (or did) they major in? (Assume an AU where they're a normal Earth kid.)
I think the only formal education C.C. had was with the nun who eventually made her immortal. At some point in before that, she learned "some letters", but the nun gave her some more structured lessons. (Probably Bible studies, dancing, proper grammar, etc. -- things that were appropriate for girls to know at that time.) She has knowledge on a wide range of topics, but it's just by virtue of 700+ years of experience. She probably attended some classes, but not in any regular way that would get her a diploma/degree/etc.