Just as the pp said that the shortest wait to see "A Christmas Fantasy" parade is around IASWH. You can get a front row spot on the parade route about 15-30 minutes until the parade starts. But if you do it on MS, it can be at least an hour wait since that is the most popular area to watch the parade. If you do the Holiday tour they will have seats for the parade which will be right across IASWH. Benches around MS will be at least an hour or two since people will claim the spot way in advance. Same thing goes for the fireworks if you want a bench seat instead of sitting on the ground or curb. There will be two parades during your trip so the first parade will start from IASWH towards MS Town Square and the 2nd parade will start from MS Town Square back to IASWH. It is always great to watch the parade when it starts at the entrance of where it is coming from.
The best spot to watch "Believe...In Holiday Magic" fireworks is in front of SB Castle. People would wait as long as 2+ hours for a prime spot for the fireworks. I have seen people wait as long as 3+ hour for a bench seat, but don't forget that you have to stand up for the fireworks so there is no sitting on the ground. If you are on a bench you might have to stand up just like everyone else. But you can get there around 30 minutes until the fireworks, but that is like forcing your way in. So if you want a front row spot, you got to get there at least an hour. Also if you plan on waiting a while on the curb side for the fireworks, you can use a blanket and mark it as your territory while the rest of your party can go on rides, food, restroom, etc. while waiting for the fireworks. This is a good way to save spots for your party so other groups won't try to force their way in your area. If you get there early, they will have Sleeping Beauty Winter Castle show which is a light up show of the castle before "Believe...In Holiday Magic" fireworks. There will be two shows a night before the fireworks and it does snow around the castle area.
For the Holiday Tour, I don't think that it will be boring for kids since the CMs will try to make it more exciting for the young ones. But the highlight of the tour is definitely the seats for "A Christmas Fantasy" parade.