As far as the office suite goes, find out what format her school want home work doing in if she’s going to be submitting it electronically, or working on it at school. I can guarantee that answer will be MS Word. In that case, buy Mac Office and use the education discount because she’s at school. Yes, it costs more than the free options, but at least you’ll know that exactly what is on her screen will be what the teacher sees. Good as the free options are, and Pages for that matter, they still don’t get it quite right.
As far as messaging goes, find out what her mates use. Then install that. At least she’ll be able to talk to people then. Personally I use Skype and iChat/Facetime for video, depends on who I’m talking to as contacts have accounts with both.
I second the suggestion to make your daughter a normal user on it too. You can then do clever things like lock down access to applications to certain times. So if you don’t want her video chatting her mates after 9pm, then you can prevent the app from even running.
Use Safari for the web browser. Firefox eats memory and just generally doesn’t react as fast as Safari. Chrome does react a little faster, but pages seem to render in the same time as Safari. More crucially though, the ad blockers and flash blockers aren’t as good as they are on Safari.