Please find the explanation given below for your queries.
The SYSPRINT DD statement defines a sequential data set that is used for output reports. Reports that are generated by the LIST command are written to the SYSPRINT DD statement. You can assign SYSPRINT to sysout or to any sequential data set.
COBOL programs that are compiled with the NORES compiler option, dump output generated using SYMDMP remains the same and continues to be directed to SYSDBOUT. If the RES compiler option is used, a CEEDUMP will be produced instead.
When using the OBJECT compiler option, you can store the object code on disk as a traditional MVS data set or an HFS file or on tape. The compiler uses the file that you define in the SYSLIN or SYSPUNCH DD statement to store the object code.
//SYSPUNCH DD SYSOUT=B
B is the standard output class for punch data sets.
Whenever you are creating new GDG generation, you can specify other GDG base as your model dataset. That is specified in XX.MODEL.