Question about comparator MAX912 latch enable
Yes, what you're showing here will work in theory.

However, a high on the latch input takes a few nanoseconds to take effect, and the input should be stable during this time. 

These two effects will let you miss very short voltage spikes. 

Another thing to consider is the start-up time. If you put the circuit as it on a board and power it up, the voltages at the input and the supply voltage will not instantly be applied but ramp up slowly.

What happends during this period is pretty much undefined. Your comparator may trigger and instantly lock up. So you'll likely want some kind of switch that lets you reset the latch once it's locked. This requires a few parts around the comparator.

In the end it may be cheaper and more practical to ignore the latch feature and use a simple RS flip-flop. The S-pin goes to your comparator output and the R-pin could be connected to a power-on reset chip such as the LP3470 or so.

For the pulldown: The datasheet does not directly specify the current capabilities of the output, but they give figures for 10mA, so this current is safe. The lowest pulldown would be VSuppy / 10mA. For 5V that would be 500 Ohm. I'd just stick a 10k resistor there however. No need to burn so much current just for a pulldown.