The red lightsaber angle is quite interesting.
Everything you said here is very interesting. I have even already cut the line “Not again! Obi-Wan is gonna kill me.” So it would be so easy to have that happen narratively (he wouldn’t say that if he knew he needed to hide his lightsaber). My only problem is finding a reaction shot of Anakin with the appropriate emotions on his face. He needs to look at the lightsaber the next time we see him use it (on Geonosis) and have some kind of emotional reaction to the permanent change in color, either fear or confusion, I would say.
It would be very time consuming for me. I don’t know how others do it, but I’m going through frame by frame to change the color. I’m not saying I won’t do it, but I need to be certain it would be better than returning to its blue colour without an explanation before I even try.
Alternatively, his lightsaber could flash red several time during the last time he uses it, and then it is fair to say Anakin didn’t notice in the heat of the battle, meaning that reaction shot I was talking about isn’t needed.