Ktoon seems to be mainly for Linux. I went to their website which seems to be mostly in Spanish you can click the English tab, however it seems several languages were mixed together, which made reading the website hard. I went to the user video example gallery and there was 1 video posted. Now if the software was easy to use, you would think there would be a large number of videos from users, since after all it is free. I also searched youtube for examples and I did find a few, mostly stick men type animations. I did not find very many tutorials either, so I will pass on this one.
Synfig looks promising, however doing research I notice that it does not handle sound. Now for music and such that should not be a problem, however for lip-sync I would think it would raise a lot of problems. How can you animate the lip-sync without being able to work with it in the animation program? Synfig had much more examples, both on youtube and on the main website.
Below is a Synfig eye animation, I think it looks very good. However, not having audio in the program makes me Leary.
Pencil seems to have a pretty good following. However, pencil is a frame by frame animation software. I was hoping to use the power of the computer to do the in between frames. So I will keep looking.
Finding the right software seems to me is probably one of the most important aspects of this project. After all it is a tool that will be used day in and day out to produce the cartoon. Most likely there will be several types of software. One for animation, maybe one for audio [if not included with the animation software] Then there is video editing software, maybe special effects software. Perhaps even some software to keep me organized, as you do not want to spend a week animating something only to realize at the end that you animated yourself into a corner and the week was wasted.
I like the idea of using open source or free software. However, I worry that they may not have the features I need, or may be hard to learn with little documentation.
I am leaning toward 2d animation, as 3d seems like it would be harder to learn. I understand the concept of 2d animation better as it is what I have watched most my life. I still remember when I first saw Toy story, how I stood in awe of what I was seeing. Being able to reproduce that effect would be awesome, but I have also seen homemade 3d animation and the medium seems to be less forgiving than 2d.
Ktoon, synfig and pencil are 3 open source 2d programs. I will check these out and give my impressions of them soon.