Existing Database (11.2.0.3) Can Be Upgraded As Pluggable Database And Plug It In CDB?

I would like to know about oracle 12c. In 12c, when i read documents,i understood that one container DB(CDB) can contain upto 253 pluggable DB and this pluggable DB(PDB) is similar to our traditional database(pre 12c).

1) whether my existing database (11.2.0.3) can be upgraded as pluggable DB and plugged it in CDB?

2)i read that we can move from local data center model to cloud in this version. Is that mean that once PDB is ready, whether we can plug it in CDB using private cloud or public also possible?

3)If public cloud is possible, are both CDB and PDB accessed through cloud client only?If so, whether our user data that is available under PDB also moved to external place?