2D still Image animation (Photoshop - After Effects integration)

Hy everybody,
this time I'd like ti suggest a tutorial (or course) about 2D still Image animation. What do I mean?
This link will show you what I'd like to obtain:
http://www.youtube.com/watch?v=a06tXzCMeHs
http://www.youtube.com/watch?v=xgjper94nec
http://www.youtube.com/watch?v=mjYAlhcC1HI
http://www.youtube.com/watch?v=HStMvs02NVc
http://www.youtube.com/watch?v=pfYQ-Cp7atw
http://www.youtube.com/watch?v=eZ9uQuDo23E&feature=related
http://www.youtube.com/watch?v=0ECXdhlIYqY

Naturally I just know many techniques about it, but I'd like to make this type of process ...better!
Above all:
1 ) In Photoshop, how to separate ( to contour) VERY GOOD any part of entire still image (that sometimes are old photo or paints... like old maps, antique prints, and so on...)?
2) How to create a RIGHT Clean Plate to recreate a credible Background?
3) How mapping in Photoshop (by Vanishing point ...?) or in After Effects (by Grid..?) the original perspective to locate in the best way the part of entire still image (crop layer) made in Photoshop?
4) How to use a GREAT Depth focus to create suggestive shots and camera movements!
5) How to add environmental effect like fogs, smokes, moving items (like cars, animals, plants, tec...) with Particle , Puppet tools, and so on...?

Many thanks for your replay!