In the novel; Did you know that When Renji and Rukia announced their marriage at "The Safflower," Nearly everyone they told was completely unsurprised by the news ?ππ
Only Hanataro and Hisagi were shocked (Hanataro briefly fainted, and Hisagi was called a "thickhead" for not figuring it out). Those who had already figured it out and were not surprised included :
βRangiku: Smirked and immediately knew it was coming when Renji sent the morning email without specifying what the "important announcement" was
Yumichika and Ikkaku: Figured out that an unspecified announcement meant a wedding.
βHinamori Momo: Agreed with Yumichika and easily deduced the news beforehand.
βKiyone Kotetsu: Realized it as soon as she saw the high-class, formal setting of the restaurant.
βKira Izuru: Put together the luxurious location with the nature of the gathering.
βHitsugaya Toshiro: Remained calm and supportive throughout, not showing any surprise
At the Captains' Meeting (Chapter 14)
When Kyoraku announced the news to the Gotei 13 captains, he popped a party cracker expecting a big reaction, only to be dejected when literally every captain already knewπππ:
βSoi Fon: Stated it was only natural she had intelligence on the matter.
βRose: Already heard it from his lieutenant, Izuru Kira
βKotetsu Isane: Already received the news from Rukia and Renji directly.
βHirako Shinji: Already knew through Hinamori
βIba Tetsuzaemon: Was already personally greeted and told by the couple
βYadomaru Lisa: Already knew (and was already taking wedding-kimono accessory orders from Rangiku)
βMuguruma Kensei: Knew because Hisagi was desperately asking to run a magazine feature on it
βZaraki Kenpachi: Knew because Ikkaku and Yumichika wouldn't stop talking about it
βKurotsuchi Mayuri: Knew everything, including Urahara's secret gift to them
βKuchiki Byakuya: Had already personally approved the marriage, processed the paperwork, paid for the restaurant, and secretly scheduled their ceremony.