I have answers to some of your questions and some tutorials. Hopefully they help.
No. 1 - https://youtu.be/qkYATpclg4E
No. 2 - You can use the TextBox and store the value
No. 3 -https://youtu.be/_boq4iZKucs or https://youtu.be/k-H86sVusw8
No. 4 - http://appinventor.mit.edu/explore/teach/coordxplore
No. 5 - STILL IN PROGRESS: Random number without repeat
No. 6 - You can use the Camera feature
No. 7 - https://youtu.be/Fnj0Axhn9xk and Is there a FREE Email Extension or Messaging that I can use?