Well, one could argue that the present constitution is technically a heavily-amended Meiji Constitution. After all, it was adopted the same way as a Meiji amendment would. The Emperor introduced it, and passed with a two thirds majority in both Houses.
For some reason Japan surrenders after Midway, Perhaps they lose everything they have there. The USA would most likely be more lenient. Also don't rape Nanjing.
Easy enough. ISOT me back to 2009 and prevent the death of Hirobumi Ito. All members of AH.com would be butterflied away And next? See 2009 Lost Memories