Living Dead

[Saeno]

Also keep in mind that Hallowed Ground you take no damage. Immune to knockbacks and all negative status effects.

False. You can still be knocked back while Hallowed is active and you can still receive debuffs while Hallowed is active. Only Tempered Will prevents the PLD from being knocked back.

[Chaeden]

False. You can still be knocked back while Hallowed is active and you can still receive debuffs while Hallowed is active. Only Tempered Will prevents the PLD from being knocked back.

Depends on the mechanic actually. There are a decent number of debuffs and knockbacks that explicitly only effect you if you take damage from them. The dot from Guardian being an example of something entirely removed by invulnerability, along with the vulnerability from the cyclops alike from Hell's Lid. So in some cases Hallowed will actually prevent those things....all other times when the effect isn't tied to taking at least 1 damage yes you need tempered will.