IMO Coco is wonderful. I saw it twice in theatres and hope it lasts till New Years weekend so I can see it again. FWIW, I'm a middle-aged lady from the Beaver Cleaver suburbs of middle-America and about as white/Anglo as they come; Coco uses the setting and culture of Mexico to tell a story anyone can relate to about family, love, forgiveness, growing up, and more. It reminds me of Ratatouille (which I also love) in the sense of having a more complex, adult story (not in an inappropriate sense, but in some emotional themes/story points).
I love the characters; Miguel is a totally believable and sympathetic protagonist; we are right there with him on his journey, even when he makes impulsive and ill-advised choices (like ya do) that he'll learn from - and he is not the only character who will learn and change as they go. And I seriously think Hector is one of the best Pixar characters ever (certainly one of my favorites). I can understand that Coco (like all movies) is not everyone's cup of tea, but "bland" is not a word I could imagine applying to it.
Olaf's Frozen Adventure is a cute Disney TV special. (Disclaimer: I do like Olaf.) It did not need to be in the theatre. And no matter what Disney or anyone else says, I'm still convinced they put it in front of Coco because they were afraid they couldn't sell this weird-looking movie about Mexicans and skeletons with no Princesses.
Anyway, if you haven't seen Coco, stay far away from spoilers and go. And oh, yeah, take a Kleenex.