So I'm doing the Undead Lord Cleric archetype and then because the party needs some arcane assistance, took a Level in Wizard with the Undead Master. Looking it over, one option is Corpse Bond (Su)
This ability alters arcane bond
Corpse Companion (Su)
With a ritual requiring 8 hours, an undead lord can animate a single skeleton or zombie whose Hit Dice do not exceed her cleric level. This corpse companion automatically follows her commands and does not need to be controlled by her. She cannot have more than one corpse companion at a time. It does not count against the number of Hit Dice of undead controlled by other methods.
So what I'm wondering is if the single Corpse Companion restriction applies to both class features or just 'once' for each class feature.
As written they're the same ability, and they don't say they stack for levels so they don't stack. With that said, I feel in any home game a GM should allow them to stack for level if it comes up.
However, it's mostly an academic matter since the ability is so weak that you'd never actually use it in actual play. You will always have better things to do than spend 8 hours creating the corpse companion, and they're so fragile they rarely last more than one combat encounter.