#1 - If you die while charging your ultimate it goes on full cooldown, instead of the reduced cooldown it should be on since it wasn't used. Not sure if that's a glitch or by design.
#2 - If a single person in a group has banshee's veil, the ult is prevented from hitting ANYONE. Not just the person with the shield.
1- Not a bug. If you die while ulting, its the same as getting interrupted by an enemy. This is a strategy the enemy team is suppose to employ against champions with channeled abilities. Basically, anything short of holding the charge until it goes on cool down will result in the full cool down being used. Its fair and intended and makes sense.
2- Less sure about this one, and I think the wiki isn't entirely accurate, but the champion spotlight says her ultimate can hit more than one enemy in a small area around the first target struck. It could be that because the primary target isn't getting knocked away, no one is (because the small area around the primary target doesn't exist because of banshees). If explained this way, it isn't a bug; but it might not be working as intended. Not too sure on this one.
