If you look at the synopsis of Email::MIME, you'll see that the structure of a multipart mail looks like this:

# multipart message
my @parts = (
    Email::MIME->create(
        attributes => {
            ...                    
        },
        body => io( ... )->all,
    ),
    Email::MIME->create(
        attributes => {
            ...                    
        },
        body => io( ... )->all,
    ),
);

my $email = Email::MIME->create(
    header => [ ... ],
    parts  => [ @parts ],
);
[download]

In other words, you cannot simply stick all your body parts in attributes (which needs to be a hashref, btw, not arrayref, as you have it!).  Rather, create individual parts, and stick them in parts => [ ... ].

P.S.: please use an identation that reflects the logical nesting of things...