Yes you can get the transcribed text form any youtube video.
As for copy right statements I actually try to use the Creative Commons # 4 on all my work.
Most of what I do when I post a video is not for entertainment bur for political or educational purpose.

Here is a reference to help with your steemit content
https://steemit.com/terms/@drherz/who-owns-the-content
and much more info in this next link
https://steemit.com/license/@somethingburger/licensing-steemit-content-who-owns-your-posts

Best practice is to make sure you always give source credit.
I followed you back and will watch for you post in my future timelines.

Good luck and welcome to STEEMit.

Most youtube videos will show their current lic format but not to many people pay much attention to that.
Not say you should not pay attention I am just saying that is what most people do.