This is not my field of expertise, but here goes: When TI_H goes high, the bulk of the current to charge the gate capacitance will initially flow through the 22 ohm and C16. As C16 charges, current will then flow only through the 200 ohm resistor. When T1_H goes low current will flow through the diode and the 22 ohm. So maybe what's going on here is they want the MOSFET to turn off faster than it turns on. That makes sense.
The diodes across the MOSFET are probably there because they are faster than the intrinsic diode. Why are there two in parallel? I have no idea.
The snubber is probably there to suppress voltage spikes, noise etc.