SMON could be causing that problem:

1) pctincrease for temporary tablespace as zero.
2)use temporary option for temporary tablespace.

The session waits stated below, did those occur during that 3am process, enable trace for that process and find out where the wait is, could be because of sorting or could be lots of deletes and inserts ,release of free space and usage of free space , make sure pctincrease of data tablespace is also zero.

The stated waits shows more problems:

log file sync wait and log file switch completion, this indicates two things
1) log_buffer is very high and log files are small
2) lot of modifications are happening.

Reduce log_buffer and increase log files.
Also find out if there are any dirty buffers inspected in v$sysstat.
Then u may need to increase db_writer_processes.

Take Care
GP