Lovily, well done. I've noticed (for me anyway) that multiple paintings with daytime sky hung on the same wall, and with the skies done differently on each, can still work together. BUT paintings with night sky on the same wall - and the night sky done differently in each- will seem odd, and distracting.
My guess is that we see different day skies in real life all the time and the sky is present all day - and changing - so it's not disturbing to see a series of paintings with varying daytime sky.
We don't have that level of experience with the night sky. All these work alone but -- if hung as a group on a wall -- I think not. Well, in this case, because the subject IS the sky it might, but if those skies were just the background of the painting and not the subject - it just doesn't work imo.
Case in point. I currently have three of my LARGE night paintings hanging in my living room and the night sky is treated differently in each. They barely work in the same room IMO only because they are on different walls. Even so, even though they've been up for a long time now, I still find it a bit disrupting from the ambiance I'm after -- that the skies are different.