I would say the confirmation of the details for Doreen look to be in order and likely to be truthful.
Born in hospital with complete witness details etc.
Leonard's birth was at the home Adeline shared with her mother.
No accouchier, and just a Mrs Dent certifying.
Ernest KING's birth stated to be 1887.
Ern Wm HOPE on enlistment birthdate 1888.
Ern Wm Francis HOPE date of birth at death 1890/1
Jas BOW birthdate was 1884. exactly 10 years out on Doreen's BC
Exact date of marriage given is at variance.
In my opinion, KING appears to be trying to slip into the identity of James BOW in many aspects, but does not use his name.
Violet ROBBINS in Tasmania asks James BOW, Are you the same man as Ern KING?
In 1920 in the military record of her husband (Thomas Henry LOWE) Ruth mentions her son in one of the letters from her. States his name Leonard and describes him as her other son and in another letter, my youngest son.
However Leonard uses the surname name BOW (not LOWE or KING) and it looks like she took him on when Adeline ended the BOW relationship/marriage.
None of this helps with the questions about CANNON/HOPE, regrettably

for interest's sake. Is there a resemblance? Leonard and Ern Wm HOPE