I didn't read through everything so I'm sorry if this has been said or decided already, but in my house, we try to keep consequences "same-day" for the 8 and 10 year old, and make the punishment fit the crime.
So, using those parameters, no, I would not take the trip away. At their ages, they are only doing what you as parents are allowing them to do. Don't take that the wrong way...what I mean is, they are not old enough to get into any sort of trouble that is not in their immediate environment. Unlike a teen who has the autonomy and relative freedom to get into trouble with things often beyond the parents control, 8-10 year olds do not. I am assuming that they are still monitored at all times by an adult? This makes it easier to modify their behavior because you are still relatively in control of what they are exposed to.
Here is what I would do:
1. Call a family meeting. Explain to them that you would LOVE to do fun things with them (like a trip to Disney), but you have to be sure that they can behave on a vacation.
2. in order to practice for proper vacation behavior, you need to see it at home first.
3. Here are the rules: No backtalking. Be respectful. Be kind. Be helpful. Do what Mom and Dad tell you to do. These rules are now FAMILY rules and everyone must follow them.
4. Consequences for breaking a family rule will be: (insert punishments that fit the crime, like "mom asked you to empty the dishwasher and you pouted and backtalked. The consequence for this is that you now have to empty the dishwasher AND sweep the floor." (make sure the punishment fits the crime.)
5. Follow through - Every. Single. Time. it is exhausting. The kids will feel like you are picking on them. They will fight back. You will want to stop. But DON'T. It will get better!
ETA: I now had time to go back through and read a little - I'm glad you decided to go, but I would still put a behavior plan of action in place...nobody wants to live in a home where kids are out of control!