Yes. I don't have very good conscious control of it, but if I start "daydreaming" the images can pretty much override what my eyes are seeing. I wouldn't say it's overlaying like AR, for me it's more like tuning in to a different channel. I guess somehow the things my eyes see are still registering, e.g. if something new comes into view I will pop back to reality.
I'm the same. I can pop things in and out of reality as needed to visualize things. Of course the counter to this scares me thinking about what happens if I did this without conscious awareness...
My dreams can feel more real than reality too. Like full senses lucid dreams. Looking at things like clocks and books worked in my dreams. My dreams are just a reality inside the reality everyone else shares.
Also, In my teens and early 20s I had dreams I could levitate. If you could imagine being able to follow magnetic fields just under your skin would be about the best way to describe it. It was disappointing to wake up and realize that I couldn't do this.
Yep. Super helpful for visualising structures of source code and other things. Don't close your eyes, just patch your brain output back to brain input. Same as when you're dreaming.