In-laws 😣

We are getting married late October and having our baby shower the same day so it's more convenient as our families are spread out. We've scheduled an elective 3D-4D Ultrasound for family that morning so everyone can be apart of seeing Baby girl. Well the ultrasound alone is $250! We got the package where they'll do newborn pictures once she's here too. Well me and my family are paying for literally everything! Not one dime has even been offered from his family and it irritates me. My family struggles and his is beyond well off. They want to be invited, which I'm not against, but my SO doesn't really talk to his family due to it all being drama! His step dad said if we invite his dad or that side he'll fight them, He's made multiple comments about how our child isn't even his actual grandchild so he doesn't care what happens. I'm just so ready to just say Fuck it and not invite a single person.