Mirri, Cat Warrior

Landwalk is a generic term that appears within an object’s rules text as “[type]walk,” where [type] is usually a land type, but it can also be the card type land plus any combination of land types, card types, and/or supertypes.

Landwalk is an evasion ability.

A creature with landwalk can’t be blocked as long as the defending player controls at least one land with the specified land type (as in “islandwalk”), with the specified type or supertype (as in “artifact landwalk”), without the specified type or supertype (as in “nonbasic landwalk”), or with both the specified type or supertype and the specified subtype (as in “snow swampwalk”). (See rule 509, “Declare Blockers Step.”)

Landwalk abilities don’t “cancel” one another.

Multiple instances of the same kind of landwalk on the same creature are redundant.

Vigilance is a static ability that modifies the rules for the declare attackers step.

Attacking doesn’t cause creatures with vigilance to tap. (See rule 508, “Declare Attackers Step.”)

Multiple instances of vigilance on the same creature are redundant.

First strike is a static ability that modifies the rules for the combat damage step. (See rule 510, “Combat Damage Step.”)

If at least one attacking or blocking creature has first strike or double strike (see rule 702.4) as the combat damage step begins, the only creatures that assign combat damage in that step are those with first strike or double strike. After that step, instead of proceeding to the end of combat step, the phase gets a second combat damage step. The only creatures that assign combat damage in that step are the remaining attackers and blockers that had neither first strike nor double strike as the first combat damage step began, as well as the remaining attackers and blockers that currently have double strike. After that step, the phase proceeds to the end of combat step.

Giving first strike to a creature without it after combat damage has already been dealt in the first combat damage step won’t preclude that creature from assigning combat damage in the second combat damage step. Removing first strike from a creature after it has already dealt combat damage in the first combat damage step won’t allow it to also assign combat damage in the second combat damage step (unless the creature has double strike).

Multiple instances of first strike on the same creature are redundant.