A:AnswerOnly the android style keyboard, not a separate one. I wouldn't want an external keyboard for this. You can swipe just like an android phone so it's great and much larger.
A:AnswerThere is a cover along the top right side of the tablet just to the right of the power button. You'll need something small to pry it open and the card is spring loaded. Be careful that you don't allow the spring to shoot the card out when removing or inserting it (speaking from experience)!
A:AnswerBecause they only want you to use their apps!
Luckily there are many apps that allow you to download from the Google Play Store. Since I can't post links here do a search for them on Google.
