Will the new Support items work on Sion passive?

Redemption and Knight's Vow, to be specific.

Redemption can be used while dead, and I assume that includes Sion's passive since he can use Youmuu's in that state. However, will the heal still affect him in passive?

...and with Knight's Vow, will the healing/damage redirect affect him in passive?

If both of these do, it could totally change Support Sion's gameplay. Rather than staying alive and peeling, it could be more effective to just recklessly engage into an in-progress fight, die, and your passive healing combined with Redemption and Knight's Vow healing will keep you alive for much longer to smash the enemy team with %HP damage. If the enemy team focuses you, your ADC can heal you by doing damage to them. If they focus your ADC, you mitigate some of the damage on your ADC and sustain yourself up in passive, all with the AoE burn from Redemption.

So, does this work?