Cubase iC Pro can trigger any KeyCommand that is available in Cubase.
For the first use-case you can delete the latest recorded part either by assigning a KeyCommand button to Delete or simply Undo (there are already factory presets for this latter one).
For the second use-case, unless I’ve got you wrong, you have a KeyCommand for deleting aftertouch data named “del.aftertouch” that you can assign to a KeyCommand button as well (and eventually rename).