I just did mine, did a few of the navs at night, ( i think minium of 1 has to be )
I wanted to do it all at night too, but the instructors tend to like to be able to see things with they,
1 shut the engine down for the feather and;
2 "fail" the engine on just about every approach.
I dont think there isnt any reason the whole thing cant be done at night. But I found a mix of day and night was good.
Just talk to the schools and see what their take on it is.