Well, "Order of Undead" will be better than your barbarian luck :)), some kind of "Fear" or "War Cry" spell, magic resistance and luck can still be boosted somehow.

To pump up unnecessary barbarian luck, you need level 1 (that is, it's only there for the sake of it, it could have been removed from the proposed build - I didn't notice), to pump up "Order of Undead" you need 4 more levels - there's a difference (of which 3 are unnecessary)! Think about it. Here, only "Bless" is better, if the elf doesn't find "Darkness".
Luck only needs resistance, if the elf doesn't go into light (and +2 will be given with the artifact +2 +4 and visits - elf artifacts +5 luck will increase the orc's attack by 50%). Reconnaissance is needed (not a perk, but simply an attack with a secondary hero), before re-pumping, to know what's what.

By the way, are Krag and "Order of Undead" compatible? Who knows? I've heard something bad about it...