Emperor Akihito, accompanied by Empress Michiko, will visit the mausoleum of Emperor Showa (Hirohito) on April 23rd to report his abdication. Visits to the mausoleums of Emperors Komei, Meiji, and Taisho are planned after abdication.
Source:
Sankei
Nobutake Odano (71) current grand master of Crown Prince Naruhito's household, will become grand chamberlain to the new Emperor and Empress.
Mr. Odano is a Keio University graduate, worked for the Ministry of Foreign Affairs from 1970-2012, and served as ambassador to Myanmar and then the European Union. He joined the IHA in September 2012 as Grand Master of Ceremonies and was appointed to lead the Crown Prince's household in May 2016. In addition, Mr. Odano has advisory roles at Kintetsu Group Holdings and Otsuka Pharmaceutical.
Chikao Kawai (66) current grand chamberlain to Emperor Akihito and Empress Michiko, will continue as grand chamberlain to the new Emperor Emeritus and Empress Emerita.
Mr. Kawai graduated from Hitotsubashi University, worked for the Ministry of Foreign Affairs (1975-2013), serving the Southeast Asia, Asian Affairs, and North American departments with a stint as special envoy to the United States in 2001. He joined the IHA in September 2014 and become grand chamberlain to Emperor Akihito and Empress Michiko in May 2015. Other roles include advisory positions at Ito En, Ltd and the Foreign Ministry.
Takaharu Kachi (66) current director of the Imperial branch households, will become grand master of the new Crown Prince household. I didn't find much info on him except he announced Prince Mikasa's death in 2016 and Princess Ayako's engagement in 2018.
Sources:
Jiji
Odano Eyed as Grand Chamberlain to New Emperor, Empress | Nippon.com
Odano Nobutake - Japan Wikipedia
Kawai Chikao - Japan Wikipedia
On March 11th, the IHA announced the official way to refer to Prince Akishino and family in Japanese. I don't know the exact English translation so here's my best guess:
秋篠宮皇嗣殿下 -> Akishinonomiya koshi denka -> His Imperial Highness Crown Prince Akishino
Addressing him as 秋篠宮殿下 "Akishino no miya denka" or 皇嗣殿下 "Koshi-denka" are accepted.
秋篠宮皇嗣同妃両殿下 -> Akishinonomiya koshi dohi ryō denka -> Their Imperial Highnesses Crown Prince and Princess Akishino
秋篠宮皇嗣妃殿下 -> Akishinonomiya kōshi hi denka -> Her Imperial Highness Crown Princess Akishino
No changes to Mako, Kako, and Hisahito; they still use 秋篠宮 Akishino-no-miya.
The house and residence remain 秋篠宮家 Akishino-no-miya House and 秋篠宮邸 Akishino-no-miya Residence (aka Prince Akishino Residence)
Source:
Jiji
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I rarely hear "denka" in news clips so I assume media will call Prince Akishino "Koshi-sama" and the rest of the family: Koshi + Akishino-no-miya + Kiko-sama, Mako-sama, Kako-sama, and Hisahito-sama.