Yes. It is difficult to get at, but you know that having removed the cable!
There is a single hex head screw (7/16" AF) next to the cable hole. This
holds the egg shaped plate on. With this removed you can lift the gear out.

Yes... and I don't think it's THAT hard. You can reach up and over the
left-hand axle and remove it with a socket (though it's slow given you can't
rotate much per turn. That's for the drive gear.

For the cable, it's easier and can be done from below or above. Sometimes
the ferrel (sp?) can be tight and takes a bit of effort. It's very awkward
from below though you can (roll under from the front on your back and slip
your left hand around the axle and you can get a couple of fingers on it). I
think it's easier to reach down the back of the engine. If the cable is
badly stuck, then, yes, it's better to remove the little plate that holds
the drive gear in the transmission (held by one nut).