Seraphic Steed

Lifelink is a static ability.

Damage dealt by a source with lifelink causes that source’s controller, or its owner if it has no controller, to gain that much life (in addition to any other results that damage causes). See rule 120.3.

If an object changes zones before an effect causes it to deal damage, its last known information is used to determine whether it had lifelink.

The lifelink rules function no matter what zone an object with lifelink deals damage from.

If multiple sources with lifelink deal damage at the same time, they cause separate life gain events (see rules 119.9–10).

Multiple instances of lifelink on the same object are redundant.

Saddle is an activated ability. “Saddle N” means “Tap any number of other untapped creatures you control with power N or greater: This permanent becomes saddled until end of turn. Activate only as a sorcery.”

Saddled is a designation that has no rules meaning other than to act as a marker that spells and abilities can identify. Only permanents can be or become saddled. Once a permanent has become saddled, it stays saddled until the end of the turn or it leaves the battlefield. Being saddled is not a part of the permanent’s copiable values.

A creature “saddles” a permanent as it’s tapped to pay the cost to activate a permanent’s saddle ability.

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.