[Espeefan]

Yes, you can do exactly that, if you like, though if you want to be on the safe side with current draw on the track drive, maybe think about stepping up to the next biggest Sabertooth ESC, if money permits.

I would also think about using the blade and ripper servos as actual servos, with no ESC running them. Unless you need more travel to raise and lower the attachments. You can always increase the travel/throw of the servo by using a longer servo arm, with the attaching linkage out to the furthest hole, though you'll loose a little leverage (torque). If you run your blade and ripper servos with an ESC, there will be nothing to stop the servos from rotating past or over center, except you the operator, and that may or may not matter. It's something to think about though.