Does Prove Thyself Stack?

Prove Thyself does not stack with other instances of itself. May be unlocked in the Shrine of Secrets or in Dwight's Bloodweb at Level 35.

Does Leader stack DBD?

Leader does not stack with other instances of itself. You are able to organise a team to cooperate more efficiently. When other Survivors are within 8 metres of you, Leader increases their Action speeds for Healing, Sabotaging, Unhooking, Cleansing, Opening, and Unlocking actions by several percent.

How long does it take to finish a generator with prove thyself?

If four Survivors work on a Generator while using the Perk Prove Thyself (Teachable Perk of Dwight Fairfield), it only takes 25.08 seconds to fully repair the Generator. If only three Survivors work on it, it takes slightly longer, about 29.3 seconds in total.