HKVO is very efficient and it will depend on each individual application.
Maybe 3 months from receiving the application if everything goes well.
Though it can be held up with security/background checks that are completed by a third party.
IRCC has no control over that and you just have to wait. Hopefully the applicant has no complicated
history. If they call you in for an interview that means there are some concerns with your application
and you can expect longer times......... Be prepared!
I am aware of a HKVO outland application in my area last year. Start to finish 7 months. ( having fun in the snow now )
Maybe you get lucky and no interview.
Good things to come!