Enter your page name on Facebook's search textfield then click on "About"
Then you should be able to see your Facebook page Id. Just copy/past it to live-poll.net registration form
If you are looking for a complete solution with custom features and design, the custom offer suits better your needs than the generic offer. In fact we can take care of everything even the broadcasting. Using generic offer you will have to handle the live poll broadcasting and all settings. Generic offer is more adapted for a personnal use than custom offer.
No, an API Key only works for one page. If you want to do various live polls on multiple pages you will need to purchase as many as necessary.
A live poll can have a maximal duraction up to 4 hours. If you exceed duration of 4 hours, your facebook live poll won't be saved to the videos of your Facebook page.