My friends took a small backpack to DL, it held like 2 bottles of water, a few snacks and their wallets etc. Is a small back pack a good idea, could I take a larger one or are they a pain in the butt with the rides? I know there are lockers but frankly, THAT would be a pain in the butt too, as we have little ones and would like to have the stuff on hand at all times. I have a gweeby fanny pack, are they still used? Being Canadian we are supposed to have our passports on us at all times, I am scared of losing it though...but thought the fanny pack would be the way to go. THANK YOU!
How old are your little ones? Will they be in a stroller. Frankly, I would use the basket of the stroller to hold things like your jackets, etc. Keep in mind though, when I first took my DS, (who was 1 at the time), you need to keep things accessible for kids if you need them, i.e. a diaper, juice cup, blankie, etc. I thought I would use a diaper bag instead of carting around a backpack, and that was a huge mistake. I hated digging in the diaper bag, in the bottom of the stroller, that was underneath all our coats etc, and then having to carry a diaper & spare change of clothes/pajamas into the bathroom in my hands while carry my DS. If I would have had a backpack with a few essentials in it, I could have just worn that it the bathrooms, (or restaurants, or wherever else you need to be) and not worried about trying to find things in the middle of tons of people glaring at you because you are in their way.
Also, I do not care for lockers. They always seem to be an inconvenience to me, but for bigger things such as souvenirs or jackets that you don't want stolen or lost, it might be a VERY good investment to pay $5 (or however much they are) to keep those things safe. If you do have a backpack big enough to fit your smaller souvenirs and keepsakes, then you know they will be safe, just be careful that they do not get broken/bent/squished when you bring your bag on a ride.
In years past, pre-DS, I took a backpack and although it was a little awkward at times, I greatly appreciated having it with me and having plenty of room to put my goodies. Tip: just try to keep your bag as empty as possible in the mornings so it is not to heavy and you have plenty of room to put in a sweater or any souvenirs you might pick up.
Don't expect any of the kids to carry there own bag though, I think that would be asking for something to get lost. Often kids can't wear fanny packs/backpacks for as long as an adult would be able to tolerate. And plus, you will want lots of good pic opportunities for the kids without bags!