exactly what are my odds of having an engine failure at night
No body is much interested in the odds of a night engine failure, they're interested in your ability to get them on the ground in one piece. With all the lights on the Vegas strip you can hardly call it "night", try out in the middle of the GAFA on a moonless night.
Now imagine it happening at an unplanned moment where you have to select a suitable landing area in the dark AND THEN carry out an EOL you can walk away from
Single engine Huey we used 35 knots for the auto night/IMC with the landing light pre positioned to hopefully give you enough warning for a pitch pull, not knowing if you were going into trees or a clear area. Don't recall ever doing it to the ground at night in training as it was a long, long time ago.