A.,
If you stated it's "Her" day. Let her choose. It's still a party, right, not a play date? Just on a smaller scale?
I would get a babysitter to take care of the 3 and 5 year old as they do NOT have the same interests and you will NOT be able to focus on your 8 year old. You will be watching the 3 and 5 year old. And I don't know ANY laser tag that will allow anyone under 7 in to play any way.
If she chooses a movie - I again would NOT want the 3 and 5 year old there.
I would suggest a manicure pedicure party...find out how many friends and if there is a place nearby that can accommodate your group...even check into the local beauty school - it will keep costs down and everyone will still have fun!
Happy Birthday to your daughter!!