Hi Everyone!
We just sent out our save the dates and our guest list is at 130, but I also just realized a possible etiquette mistake after reading blogs so I am scrambling to make a decision.
Basically, our venue is flexible on guests up to 200, and no requirements on minimum age. We originally wanted a max of 100, but it just grew... Our wedding will be kid friendly since a lot of our friends are married with kids ranging from 2yr olds to 15yr olds. The issue is that we are inviting entire families of I'd estimate 85% of couples attending. All of our friend's kids are invited but when we split up the list he forgot to account for his cousins children and groomsmen's step children. We are using The Knot and I have already put the RSVP live, so people should be able to see (if they want), who is invited in case the addressing wasn't clear enough (we used "The ___ Family" if kids were invited or Mr. ___ and Mrs.___ etc... for couples only). Basically, should I invite all the kids and just make it open to all? It would add about 25-30 at least to our list, but the other issue is that he has a lot of cousins, and we only invited maybe 30% of them, so I don't want it to feel like if we had cut down on kids (no kids wedding besides kids in the wedding party), that we could have invited all his cousins. I feel like we did a major mess up on the guess list, and I just want to fix it to avoid any feelings getting hurt. It would go over budget and easily over 200 to invite all the cousins and all the kids.
The only thing that would change is our catering cost ($30/plate no kid discount), alcohol cost ($30/person), and increase cake size ($4/per person). Our budget is fine to go to 200 people if we had to, but the issue is the venue. Also, I'm sure we will get some declines, we would never over invite past the venue capacity of 200, but I know if we invited everyone, we'd be looking low 220-230s ish.
Any advice would be greatly appreciated! 
