1. what library give me 'screen-mode choice' requestor
asl.library is the system standard.
2. what library can give me easy way to png viewing
If you use datatypes.library, you can display any format. There are examples in the 3.1 NDK, and probably the 3.5 and 3.9 ones, too.
3. how i can create 'raw picrutes(sprites,etc)' (i mean editor),
and how i can load/view on screen it (library too i think ?)
Just use your regular paint package, then use PicCon (from aminet) to convert it to whatever format you need.
4. what library can give me easy way to work with mouse/joystick.
(i mean chords/button work)
Read the mouse though intuition.library and IDCMP. For joystick, use lowlevel.library. Once again, consult the autodocs, Rom Kernel Reference manual, and NDKs.
I suggest you buy the Developer CD. Its available from a lot of Amiga online stores. It has the Rom Kernel Reference manuals and examples, which tell you how to draw graphics and text, read input devices and all the other stuff you want to do with AmigaOS.
Also, keep an eye out on ebay for a set of printed Rom Kernel Reference Manuals, as they're quite often more convenient than the ones on the CD.