Balduvian War-Makers

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.

Rampage is a triggered ability. “Rampage N” means “Whenever this creature becomes blocked, it gets +N/+N until end of turn for each creature blocking it beyond the first.” (See rule 509, “Declare Blockers Step.”)

The rampage bonus is calculated only once per combat, when the triggered ability resolves. Adding or removing blockers later in combat won’t change the bonus.

If a creature has multiple instances of rampage, each triggers separately.