May I use this mod when streaming/recording video?

Yes!

Will you add animations for the 'Jetpack' mod?

I would, if it didn't require overwriting the jetpack/flying animation for all other character/skin mods you have installed. The author(s) of the 'Jetpack' mod would need to add a way for the animations to be replaced by character/skin helper mods (like '!skins', etc.) that would work with multiple installed character/skin mods, then character/skin mods (like this one) would be able to add their own animations.
(This is my current understanding from my research. If I got something wrong, please let me know.)