They've always been whatever role they are now. So relationships would be determined by canon ties.
Long answer. You can try to integrate facets of their personalities with those of their roles (like Steve Rogers might be prone to speeches. Maria Hill might keep fastidious records, etc.) And they may find themselves drawn to people they were very close to before this scenario (or subconsciously disliking rivals), but it's not anything they could really put a name to.