Going to be honest and say Suzuran's dad would be among the worst possible picks for a Higashi event. Assuming it does end up being the Summer event, you really want a married man for your Summer 6*? You want the big release to be a character that all the discourse and art will just be him with Suzu and Vulpis? He's not even interesting from what we know, he's just a priest with a rare bloodline (doesn't even seem like it does anything special from Suzuran). If he was a side 5* character that briefly appears, fine, but I don't want the focus on Higashi to be wasted with bullshit no one actually cares about beyond the family dynamic.