Yes 2 x 16 GB SDHC cards will work in the n800 (OS2008).

There is no word processor (you can try abiword though). Then again if your campus has online there's always Google Docs or Zoho Writer.

Leaving the messages on server while still downloading them to the n800 is called IMAP. The default email client isn't that great but there's Claws or Modest.

The n800 has a mini USB port (female and set to receive only), so if you want to use a USB keyboard you'd have to get a mini USB to USB adaptor (which will also switch the n800 from receive only to transmit as well). The dongles can be found in another forum thread here (they work pretty well).