HasteHaste 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. (CR 702.10)
MentorMentor is a triggered ability. “Mentor” means “Whenever this creature attacks, put a +1/+1 counter on target attacking creature with power less than this creature’s power.”
If a creature has multiple instances of mentor, each triggers separately.
An ability that triggers whenever a creature mentors another creature triggers whenever a mentor ability whose source is the first creature and whose target is the second creature resolves. (CR 702.134) (Whenever this creature attacks, put a +1/+1
counterTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on target attacking creature with lesser power.)