High Speed Input Protection (High Impedance, 12 V Tolerant, ESD-Safe)
I would not use both a zener and a TVS diode. Seems a little pointless. Just one or the other.

One thing you can do is stick a regular diode in series with the zener. The regular diode should have a much smaller capacitance. With two capacitor in series, the smaller one will dominate similar to two resistors in parallel. The more you stick in series the smaller it gets as well. I believe there is a speed tradeoff though since the diode entering forward conduction is slower than the TVS or zener entering breakdown.

You can also put a resistor between the component input and the TVS/zener. A series resistor between connector and TVS limits the current going through the TVS, but a resistor between the TVS and the component allows the TVS/zener capacitance to charge faster and works with the parasitic capacitance of the component input as an RC filter "to catch" leftovers from the TVS. You basically trade power handling for speed.

You can also use a ferrite bead instead of a resistor but this will only help with your transient protection. This will speed things up but won't help with your continuous protection goals.

It seems you are aiming for a current of 15-17mA during continuous protection. I would aim higher. Maybe 30mA or even 50mA. With 7V being dissipated across the diode in breakdown that's 210mW to 350mW which it should be able to handle (depending on your device I guess). That would allow a smaller series resistor for more speed.