I'm a huge fan of Obra Dinn. Got to get this out of the way first :). And it's always great to see your thought process. It's funny because I'm working on a Playdate game too, and I was tempted to over engineer everything at first but then realized that at the small resolution in one bit, you may just be better brute forcing your way through.
I've seen that you mention ios Apps for pixel art and I thought I'd share Art Studio Pro, which after many hours of research, is to me is by far the best suited on iOS for pixel art. It has all the fancy layers, multiple undos, sophisticated masking and color tools of Photoshop, but it's also managing pixel perfect brushes flawlessly, which I found is a problem in Procreate. Art Studio Pro even has a Nearest neighbor algorithm for layer transforms, which Photoshop doesn't.
Here's a few screenshots:
Sky shapes by masking a dithering pattern
Nearest Neighbor Rotation yay