Cannot concatenate videos ffmpeg
Solution 1:
I know this is probably not the answer you are looking for but why not use video editing software to do this? Video editing can take different frame rates, codecs, etc and combine them into the target format and it will be playable by ordinary software. A number of programs offer batch mode if you need to add the disclaimer to a bunch of videos.
There are free open source video editors and proprietary. I think what you are doing is way outside of what concatenate was designed for which is basically combine files of the same type and format.