[Unclear] Issues with Tahm abilities

Hey Riot, there are some strange interactions with some of Tahm Kench's abilities that aren't covered by the tooltips, so I didn't know if they were bugs or not:

1. Q-W combo will make Q do 0 damage
2. R active will put W on cooldown for a couple of seconds after arriving at the destination
3. Double-tapping W will very frequently result in eating and immediately dropping an enemy unit directly under Tahm without dealing any damage to it
4. Sometimes Q will go straight through enemy champions that were just released from W - it is as if they are being dropped so close to Tahm that they are inside the hit box. Please either make Q hit targets closer to Tahm or spit enemy champions a small distance (like 50 units) further away
5. It seems like W prioritizes allied champions over 3-stack enemy champions (at least when using fast cast). Can this be adjusted to make it easier to pick up the intended target?