There's no hard and fast rule here. If you and your daughter have a relationship with the principal (and assistant principals), you should feel comfortable inviting them.
I have been on the PTO at our high school as President for 4 years and know and worked with many administrative people at the high school. Is it appropriate to invite our high school principal to my daughters HS grad party? I will not have a child at the school from this point on.
If yes, should I also invite the 3 Assistant Principals who I also worked with closely and have excellent relationships with all?