If you rebleached without fixing you should definitely see a difference - in that you shouldn't even see the darkness anymore. However, you NEED to fix or that rehalogenated could technically print out since its now "live" again.
If you saw no difference with your bleaching, and your negs sure look to me like they have silver in them, then your bleach is toast. Bleaching should make the visible silver go nearly invisible. Redeving will bring the silver back to the metallic state OR fixing will remove it permanently.
I'd make it a priority to figure out what's going on as if the silver is in the rehalogenated state without being fixed that's a bad thing. There's no risk though if your bleach is toast because its still metallic silver.
That being said it seems pretty unlikely your flexicolor bleach just decided to stop working, especially considering it's not a blix.
Stop worrying about grain, resolution, sharpness, and everything else that doesn't have a damn thing to do with substance.