Does 2Do support syncing with Exchange?

No. 2Do currently only supports syncing with CalDAV servers (such as Fruux, Yahoo!, SabreDAV, Oracle, iCloud CalDAV and so on), Dropbox, and Toodledo.

Adding an Exchange account to the iOS Calendar app can make its events available in 2Do's Calendar Events view, but it does not enable Exchange task synchronization in 2Do.