League-of-legends – Does the Mark on Shyvana’s Flame Breath proc Spellvamp

Okay, from my experiments, it goes:

Armor/MR reductions <--> Percentage Reductions
(They stack multiplicatively, so order is irrelevant)

Flat Reductions

This makes sense, since if flat reduction was the first thing applied, after armor, it may have failed to provide a benefit at all (since, for instance, the difference between 50 * 27% and 48 * 27% is minute at best. 50 and 27% being the base attack damage of Ezreal and the armor of Amumu, my two test characters.)

Shields act as health, and damage done to shields is likewise reduced by armor / magic resist. (Meaning shields on tanks can generally absorb more punishment than shields on squishies)

The Spell Vamp portion of the LoL Wiki and my own experience show that

[Spell Vamp] works off of activated item effects, summoner spells, and abilities, regardless of the type of damage done.

Therefore, items that give proc effects to attacks like Bloodrazor, Wit's End, Malady, Wriggles etc, will NOT grant the user health through spell vamp.

On a side note, Ezreal's Mystic Shot (Q) applies on hit effects, including but not limited to, lifesteal.