That MOSFET has much more honest specs than the first few that popped up in DigiKey. It should work for you even when it's at boiling water temperatures, which it shouldn't get to unless you start running the flash at video speeds.
It may work, but I suspect you have some tweaking to do. Your voltages and currents have changed -- you mention 100V at the start, but I see a 35V supply, and that 1.5 ohm drain resistor implies no more than 23 amps through the LEDs. Also, you are aware that if you do draw 30A, your capacitor voltage will drop by 15V in your 500us? You may want to invest in a bigger cap there. It'd be a good idea to double-check capacitor ESR, too -- you could end up dropping a substantial voltage in the cap with a high ESR.
For all my snarking about details it certainly looks like you have a good starting point.