The wiki has now been updated, and Bradley's relationship type changed to "Casual / Dominant FWB". I think that's probably more accurate, and the "Romantic" route it mentioned before was just incorrect.
Viewing post in Lust Odyssey (NSFW Visual Novel) comments
I just can't get the party interactions to work, once I beat the warlord I go to the bar and then to the beach when celebrations are but the day just pass by without any interactions at all, dk if I'm doing something wrong or missing something, I'm currently in my 3rd run trying to trigger those events and nothing, neither the bar scene, the spy cam on Arthur with Phoenix and Bradley or the beach party are triggering, idk what to do
Huh? The beach party doesn't have anything to do with the bar. You just go to Sammuel and tell him you want a beach party. There *is* a scene at the beach involving the bar, but that's just with Katari.
I guess it's possible you need to have visited the bar for the option with Sammuel to be visible? I don't know.