Learning shake or AE to do specific tasks

Hello to everyone, I have tree specific problems to reselve in a documentary I am doing miself and dont have experience with after effects or Shake, so I have to learn the any of the two programs from the beggining and I just want to go in the quickest and good direction, from what I have read so far i guess is probably shake

1) I hve some moving up and down subtitles in old TV footage, I want make then dissapear

2) I have two fixed and exectly the same shots of sunset over buildings. In one of then I have a good sky and the other good buildings , I would like to merge both

3) I have a shoot with the central character in the right , I would like to move backgroung and centered this character, then use the erased background to cover the left space in the right.

I have acess to both programas. Which one you think will suit this better?

Thanks very much for your help