Deathleaper, Terror Weapon

Haste is a static ability.

If a creature has haste, it can attack even if it hasn’t been controlled by its controller continuously since their most recent turn began. (See rule 302.6.)

If a creature has haste, its controller can activate its activated abilities whose cost includes the tap symbol or the untap symbol even if that creature hasn’t been controlled by that player continuously since their most recent turn began. (See rule 302.6.)

Multiple instances of haste on the same creature are redundant.

Flash is a static ability that functions in any zone from which you could play the card it’s on. “Flash” means “You may play this card any time you could cast an instant.”

Multiple instances of flash on the same object are redundant.