Renstar, take a deep breathe babe, you sound like a typical blushing first time bride, Your ceremony will be beautiful, the reception will be a blast and it will be the time of your life because it is your day.
Now stop stressing the little stuff,

My DF jokes about me being a bridezilla and i'm like "no i'm not! no i'm not!" I will not allow myself to be one!! hehe
......Maybe not a bridezilla.....just a tad stressed.....lol. It's perfectly okay to want the day to go off without a hitch.

LOL just as long as the day is about ME and my FIANCE LOL then i'll be happy
Lol you made me remember ........My Geat Grandmother told me that Weddings are for friends and family to come together to celebrate your union it belongs to everyone especially your parents but not to you. Your marriage however is yours and nobody elses business. I rolled my eyes and said Ok Nonna, but in reflection she was right, however we didn't pay for our wedding. Although it was a fantastic wedding. We had 180 guest including children Only 40 of them were friends the rest was family, we fed our DJ, I don't think you have to but we just thought it rude not, to he also had unlimited softdrink, we were so generous, lol.

Yes you should and I'm gad to read that you are inviting your neice. Yes I think that is the right thing to do.
i ask that my sister can be respectful on my day and not have the baby crying when we are in the middle of the ceremony etc as it would be rude and would upset me because the last thing i want is a baby crying while we are saying our vows... hey,it does happen.
Honey a little unrealistic as she can't really control her, She'll probably sleep right through it. Most parents will get up and leave. It would be rude of them to stay and let them scream.

Don't want to add to your stress......
But it's a beach wedding right, is it a private beach.... just asking because if it's not you can't stop sticky beakers from coming down for a sticky and they may have screaming children with them, so maybe you need a game plan there.
Anyway don't sweat the little stuff, it will be fantastic!!!