I guess the colorful days thing was already mentioned. I must've missed that. Thanks, for showing us the topic.
I did some checking on the personal touches in One for All. I didn't check every song, but just some of the ones you mentioned about.
Like I could have sworn that Haruka doesn't smile during Kosmos Cosmos anymore
Well, it seems like all the idols (including Haruka) have the same facial expression when "haruka" was mentioned during the song. I guess they were all smiling, nonetheless.
Ritsuko doesn't wink for "watashi no megane suki kirai" in Ippai Ippai anymore.
Actually, all the idols (including Ritsuko) wink at the very end of the song.
I'm not sure if any other idols do it but Chihaya blushes for a split second on "Suki da to kizuita" in Me Ga Au Toki.
All the idols blush during that part of the song.
Though, there's one thing worth mentioning.
During Kiramekiari, there's a part where the idols shout "Guitar solo come on!!". Miki adds her "nano!!!".