Kono and Grace are more upset at having missed the boys' wedding than anything. Sure, they were supportive when Steve and Catherine were the affianced, but it was more socially-expected support than wholehearted enthusiasm.
Kono'd had the same reservations as Danno, but figured Steve was a grownup who could make his own decisions ("That's clearly where you went off the rails, Kalakaua," her mental Danny snickers).
Grace has always thought Steve was perfect for her Danno, but figured that was because of the happy princess endings Disney's been selling her whole life. She's read the original stories Grimm; she knows things don't always work out for the hero(es) of the tale.
Except, wait! Steve and Danny will just have to get married again! On the island this time, where everyone can attend.
Chin gives quiet thanks that disaster was averted. His support consists of only teasing them for a month about their combined massive obliviousness.
Mary hangs up on Steve every time he calls for a week, until Danny passes a message via Aunt Deb swearing on his mother's life that they haven't been hiding a secret relationship from her this whole time.
Lou hugs Renee and thanks his lucky stars she gave him a do-over for that first date.
Kamekona volunteers to supply 'the good grinds'.
Max quotes statistics about marriages based on friendship being more successful than those based solely on physical attraction. (Steve and Danny's heated discussion about which of them Max was calling unattractive ended in a tie. And a tickle fight.)
Rachel laughs and makes Stan admit she'd predicted it directly after Commander McGarrett's second cup of tea.
Governor Denning wonders if this will slow the mayhem down, or throw gasoline on it?
Duke scoops the HPD pot and takes his wife to the Big Island for the weekend.
Catherine sighs and packs her bags, far less surprised (or heart-broken) than she'd like to admit.