There are a couple of examples where you can combine #1 and #3 from your procedures. After the backup, you can do the prepare from the slave.
I presume by #4 you mean to configure replication from the my.cnf file? I’d suggest doing this with CHANGE MASTER TO from the mysql console to prevent conflicts/confusion with the configuration.
In short you will be doing:
Backup and copy to remote (see recipes above)
Prepare the backup (see recipes)
Start MySQL on slave
Configure replication on slave with CHANGE MASTER TO