Buffs and their affect on Illusions.
Well, someone said, that the illusions’ stats are those of your current stats (including boons). So even if you’d get fury after you summoned them , they’d get +20% crit chance, too.
I haven’t made tests myself, but afair the 30 mins fury I stole once, had a great effect.
The “5% damage when …” is another thing. No clue here.
As for sigils, getting Power & Precision (base stats) is never wrong. They’re transferred to your Illusions for sure.