In regards to the Bleach Movies (Memories of Nobody, Diamond Dust Rebellion, Fade to Black and Hell Verse) were any of them based off anything from the Manga? or are they just as much filler as the Bount Arc?
Speaking to two of those movies, I don't recall any distinct plot-advancing points within them. They explored some different concepts related to the Bleach universe (such as "Blanks" in Memories of Nobody, and the King's Seal in The Diamond Dust Rebellion), but to my recollection, there wasn't anything that was specifically canonical that the movies were based on.
Memories of Nobody is pseudo-canon, showcasing real lore elements but depicting non-canon events.
All canonical lore facts introduced in Memories of Nobody are summed in the Bleach Fandom Wiki's article on the Valley of Screams. The manga indeed confirmed in Chapter 625 that Valleys of Screams do exist ; although, contrary to the MoN movie, there are several Valleys of Screams. This is a slight lore disparity, but the general concept from the movie can be accepted as canonical : there exists pockets of space between dimensions made out of lost souls' raw spiritual energy. The Blanks entities have not been confirmed as canonical, as is Senna's existence.
Diamond Dust Rebellion is entirely non-canonical.
The Oin artifact at the core of the movie is entirely non-canonical (canonically speaking, there isn't even a "Royal Family" that could have created or possessed the artifact).
Likewise, the idea of twin Zanpakutōs is wholly impossible and directly goes against the very nature of Zanpakutos. As explained in chapters 523 to 529, shinigamis-in-training are given Asauchis, blank Zanpakutōs designed to develop themselves as such :
"All Shinigami must spend every waking moment with their own Asauchi, and as they progress in their training, they slowly and methodically imprint the essence of their soul into their Asauchi. This is how they guide and mold their own unique Zanpakutō."
This directly goes against the idea of twin Zanpakutōs developing naturally.
I haven't seen Fade to Black, although a quick cursory search indicates there are no canonical concepts introduced within the movie ; neither does it bases itself upon Rukia's actual story. If someone familiar with the movie could second this analysis, I would be quite appreciative.
Hell Verse takes place in a non-canonical version of Hell
Hell Verse's production was relatively troubled, as Kubo himself asked to be removed from the movie's credits. He felt his contribution and ideas were actively ignored by the movie's producers and directors. This intense rejection from Kubo does mean that Hell Verse is fully non-canonical and even goes directly against Tite Kubo's very own ideas. The tie-in chapter "imaginary number 01. the unforgivens" should also be non-canonical.
In this movie I was credited as "Executive Director". However honestly speaking, for the DVD version I want that title to be removed. I already asked them to do so. This is because I feel I didn't participate enough in the production of this movie to warrant such a title.I already had this feelings since the premier of the theatre version, however when I met with the producer staff to persuade them, the movie was already in the editing process so it couldn't be removed.
I had a meeting with the scriptwriter - I think it was in the year preceding the movie premiere, in early summer.The meeting was incandescent, and we discussed ideas until nearly dawn. The scriptwriter took careful notes of the ideas that I had contributed jointly during the meeting. The response was that we were able to come up with some very interesting stuff. I had the feeling that before winter at the latest the scenario would be completed - but in the end, the scenario was sent to me only in the spring of the year of the movie premiere. Furthermore, the scenario didn't contain any of the ideas of the meeting... apparently, the notes taken at that time were not transmitted to the director and to the other members of the staff.
Later on, we had some trouble with the production department agreeing to some changes decided by the scriptwriter, and the scriptwriter worked hard with the changes that were made - but unfortunately, there was no more time. The fact that characters that first made their entry in the original work like Ichigo, Kokutou and Shuuren had a very Bleach-like feeling is thanks to all of the seiyuu that gave them their voices, and to all of the staff that drew them.
Once again, thank you from the bottom of my heart.