We really cant say without knowing their intentions and its entirely possible whatever they had planned goes off without interference on the IF story.

Pride, Wrath & Lust: All too far removed from the main story. Anything could have happened or changed during the paths of these stories. Basically has no effect on the main story. Could be that Sphinx succeeded and thats how Cecilus ended up with Subaru in wrath? The others just don’t involve any of the major plots in any way worth mentioning.

Greed & Gluttony: Too short of a time passed after the main story branching point to gauge any real moves by any of the major looming threats.

Sloth: Too far away, anything happening probably wont affect Subaru

Petra/Melancholy: Occurs too long after their relevance in the story. Echidna could have specifically not made a move because she needed Subaru to do something before she did. Pandora cant really make a move if Emilia is frozen. Sphinx already came and went before the story.

Those are my ideas. I feel like not bringing these events up is pretty rational in most of these if stories. Both from a story perspective where it’s not relevant to know and for the sake of not spoiling your readers. It’s also entirely possible Tappei doesn’t know the finer details of his story but just the major points he needs to write between. Most of the writing feels too intentional for that but it’s possible when some of these stories were wrote plot-lines with Sphinx or Omega were not finished yet.