can you have a bounce house on the grass for a birthday party when you reserve a gazebo area?

Yes you can

I think so I never had parties at Anna Jean Commings park but I believe so I see bounce houses down there all the time

Hey there. This info from their website should help. Rental Information Please call (831) 454-7938 for info. A jump house may be added at the time of the reservation at Picnic Area A only. A fee and insurance requirement applies