Day vs Night spawn

As more gastlys during the night?

Tests show more ghost and dark pokemon at night

here

https://pokemongohub.net/generation-2/researching-nocturnal-specie-pokemon-go-generation-1-2/

Yes...another website did some research on thousand of spawns over a couple of days.
The found that dark and ghost mons from Gen2 spawn more often at night.

I am sure they just got everyone to write down every spawn they saw and then compiled it - I doubt they used bots and scanners to get the information of thousands of spawns in the matter of a couple of days.