# 1 Your @cmd contains sudo, but at sudo sub you are calling sudo, so you can remove sudo from commands
    my @cmd = ( "ls /tmp" ,
                "ls /var" ,
                "ls /usr" );

# 2 You can bucle your commands and execute each of them
# You need split by space your command, so system won't interpret arguments as part of the command:
    sub sudo {
        my ($label, $ssh, @cmd) = @_;
        foreach my $c (@cmd)
        {
                $ssh->system({stdin_data => "$sudo_passwords{$label}\n"},
                     'sudo', '-Skp', '', '--', split " ",$c);
        }
    }