multilicensing and relicensing doubts

[lolo]

Hi,

I have some doubts about licensing which i didn't find them solved reading
the gnu.org's site and i thought of asking them here because maybe replies
can be added there later...
(maybe i haven't find the proper urls and maybe i'm asking dumb/repetitive
questions...ignore and sorry if so)

Multilicensing:
1-Could i license something under 2 diferent copyleft compatible licenses?

1.1-Could i license something under 2 copyleft uncompatible licenses?

1.1.1-If so, Could i also add a third one to the same document?

1.1.2-Could i also license it with a fourth free, non-copyleft, gpl
compatible one?


Re-licensing:
Project 'a' was GPL when it was 1.1, now is 2.2 and has changed into LGPL,
ok?

Project 'b' was GFDL and now hasn't got any license displayed, ok?

Project 'c' was GFDL and they changed the license banner into another
copyleft uncompatible one, ok?


Thanks in advance,