Is it permissible for me to use educational materials (information, YouTube clips) from electronic sources to teach Arabic to children without the owners' permission, knowing that this might result in financial gain?

There is no harm in reading information published on the internet, in books, or newspapers, and quoting from them is a legitimate benefit that does not require special permission, as stated by Sheikh Bakr Abu Zayd. However, copying and downloading them requires explicit or customary permission, and it is safer to avoid doing so.