Shamefully, I didn't answer how you can fix that. Here ya go:

        if ($result->entries || grep(/\b$alias\b/i, @aliases)) {
            if (my ($fixed,$plusable) = $alias =~ /(.*?)([a-z]*\d+)$/i
+) {
                ++$plusable;
                $alias = $fixed.$plusable;
                print $alias;
            } elsif
[download]

Update. Ooh! Ooh!

        if ($result->entries || grep(/\b$alias\b/i, @aliases)) {
            if ($alias =~ s/([a-z]*\d+)$/my $x=$1; ++$x/ei) {
                print $alias;
            } elsif
[download]

Capturing the letters is optional. If you don't, johnq.smith9 becomes johnq.smith10. Otherwise, johnq.smith9 becomes johnq.smiti0.