Order/Luck is ok, but I'd suggest going O3/L1 or O1/L3 instead of 3 in both, as I don't think 3 in both is too synergistic. The immortal tomb king special hero and the sauromancer special hero with odd paths (can't remember the name of either now, I really would need some coffee...) are just great heroes IMO. Especially the immortal tomb king -> Holy Avenger + Bless and off he goes; if he dies he just comes back a bit more experienced
For thugging with Tomb Kings I'd suggest taking S6 to get MR+2. They are nice else, but it would suck to lose them to a horde of H1 priests banishing :P Perhaps something like W9/S6/E4 would be a nice bless LA C'tis.