My children were 10 (daughter) and 3 (son) on our last trip. They are 11 and 4 now. Main things are reinforcing the normal rules that are in place when you are out alone with them as far as staying together, when one goes we all go as far as bathroom breaks. One thing I had to go over too with my older child was staying near us in the pool so I could be within a few steps of both of them. In the parks and at Downtown Disney, I put my cell number in my daughters lanyard pocket and an ID band on my sons ankle. I took pictures of them each morning as well in case we got separated or in my sons case in case he took off running during any time we had his stroller parked. Also gave my daughter my mothers number in case anything happened to me and Disney needed to call someone back home.
One thing I dont have to deal with that would have an effect on others is the ride situation as far as what to do about the rides with height requirements. My older child has no interest in any of the rides with height restrictions so we are fine only doing things we can all do together. Unless your 2 year-old is really tall and up for a few of those, youll have to make some decisions unless your older child is like mine. I know some 2 year-olds are tall enough even though son is not yet 40 inches. So before your trip, you probably want to have a discussion with your 10 year-old about what your plan will be as far as doing the big rides. Will you skip those this trip or will he go through the line alone? At 10 he is old enough as far as Disney is concerned so its a personal decision. Hes also old enough for you to schedule a fast pass for just him for some of those rides if you decide he can go alone.
When we all do a ride together we usually ride in the same row when we can. We have so far only separated on the Magic Carpet ride. So far my son has been okay helping me shoot on Buzz and Toy Story Mania so we stayed together on those too. Not sure if we will this trip. He may be tall enough to want his own.
When we eat at QS restaurants we stick together even if it is at a place where they let someone sit and wait at a table. I usually need dds help carrying everything.
Other things that help are a quick fold stroller like the Baby jogger city mini. I use a backpack for my park bag to keep my hands free. I pretty much go at their pace.
You didnt mention if you were flying. If you are flying it is important to give yourself plenty of time. When packing think about how much you can handle if no one helps you. When they were 9 and 2 we flew down and I carried the luggage and my daughter pushed her brother in the stroller. She still wanted to push him after I checked the luggage so I let her. He had finally made the minimum height and weight for it so I rented a CARES Harness on eBay since we were taking Magical Express and that relieved me of lugging his car seat on the plane. Having the CARES harness also meant I could put him in the middle seat and we were all happier on the plane. It is also important to dress for security. I am without a belt, just earrings for jewelry. I also wear shoes I can get in and out of pretty easily. Since my son left formula and baby food behind, I just pack snacks and buy drinks after we go through security. We also have some type of gummy snack either bears or fruit snacks. My daughter says it is the best thing we have done yet for ear pressure and it is easier to get my son to eat those than to take a drink. We have our 4th trip coming up in just a few days.
