A unified Pantheon is one in which a group of divine principals are all working towards the same over-arching goal, just empowering differing pathways of achieving that goal or goals. Unified Pantheons do not necessarily dictate that every aspect of worship of a Principal part of the pantheon is aligned in every way with these goals – Principals in many cases seek other outcomes that align with the larger goals, but are not directly part of them.
In a Unified Pantheon, items made for followers of one deity can be used by the followers of others within the pantheon, even those with an Onus, unless specifically prohibited.
The Principal Pools of Blessings and Elan can be used/shared to fuel powers, but Conviction is halved for calculating what capabilities specific to the non-primary Principle may access and use via Shared Litany.