yes it is it costs nothing!!
You need unlimited data for Twitter to be free.
yes it is
yes, it is the same cost as a normal text message
If you have unlimited text with a provider the texts are free unless the company your using states otherwise for example facebook in your case. I have unlimited and it use facebook messaging on my phone and its free. So I wouldn't worry.
No, it is not.
yes
No, it only is for calling. (depends)
yes it is!..to be sure call your telephone co. and ask..if you have unlimited like I do its free..
yees
Yes, to an extent. It will cost extra to get unlimited free texting with your plan, and Verizon will still charge you extra for texting internationally.
No