Hi Marcello,
1) Follow up activities are referred to as post installation activities or post recovery activities as mentioned by step 4 in my response
2) You can build target system with different SID using the method explained
3) Yes it will work and is supported by SAP. In your scenario post restoration, you may need to start the database in upgrade mode using "startup upgrade".
Execture catupgrd.sql script. This is required as your target database version is different from source database version.
4) As explained before , you need to install target database using SWPM with ECC 6.0 SR3. Then perform restore of the database from source.
Hope this helps.
Regards,
Deepak Kori