The Swiss pronunciation of corpse is "liich", which is more or less pronounced "leech", with a Scottish "ch" as in "loch". Given how Swiss German missed a vowel shift, I'm assuming its the older German form, too.
That said, I can't htink of any Germanic Liches, only Koschei.
As for Warforged.. I'm currently using one in a game set in our world. His backstory was a bit changed around, but he started out as a bronze automaton descended from Talos of Greek mythology.