This is all correct. To clarify, Hemorrhaging Blast's 10 charges increase the damage dealt from all your bleed effects (which includes Shrap Bomb, Headshot, and the internal damage dealt by Wounding Shots as well). This is not a bug.
Not at all. The ticks are used by the INTERNAL component of Wounding shots, which only comes into play if you have Bleeds already present on the Target.
Wounding shots doesn't speed up the Ticks provided by Vital Shot and Shrap Bomb, the bonus Internal damage which uses up said HB ticks is provided by Wounding Shots, Vital Shot and Shrap bomb will continue to tick away in the background.
If a Vital shot/Shrap bomb tick takes place during the use of Wounding Shots then that too will benefit from Hemorrhaging blast.
Wounding Shot's damage is likewise increased by Cold Blooded when the target is at low life. Hope this helps!