You could use Timer2 to generate motor control signals. To get started doing that, you might consider looking at this post by Claire, and making changes to similar places in the MC33926 library to get it to work with other timers on the Uno. You could look at the ATmega328P datasheet to see what all of the timer registers do, and then you can set them up to be similar settings to those in our library. Alternatively, if you are not set on changing the library and using timers, you could also just not use the library and send PWM signals using the
One disadvantage of switching from a 16-bit timer to an 8-bit timer is that you would lose some motor speed resolution.