Harmony's reasoning for Cordial relations really stems from the help both sides have provided each other. It may look purely like ooRP favor, and to some extent it may be, but the relationship is backed by RP ingame and on the forums. Same applies to the UN.
As for Aux, they have been a key factor in the RP of not only the RP for the two SRP ships in the faction, but the viewpoint as well.