When Wielder of Water's conditional passive is checked (specifically, if one of two Wielders at a location is killed by Yasuo's attack trigger, does the remaining Wielder immediately gain the might bonus for being alone)?

Ruling: Yes, the remaining Wielder would immediately get its might bonus. Passive abilities are active whenever they meet their condition, and cleanup occurs when an item on the chain resolves.

Sequence:

• Two Wielders are at the location
• Yasuo is sent over and kills one Wielder with the attack trigger
• Cleanup occurs after the trigger resolves
• The remaining Wielder's conditional passive is checked and now applies since it's alone
• The remaining Wielder gains the might increase

Nuances:

• Shield and Wielder check at the exact same times despite shield being calculated once when a unit is designated as a defender
• State-based effects (like "while" conditions) are checked during cleanup
• Cleanup occurs when an item on the chain resolves