I have yet to upload my store to a server, hence cannot test any emails, but am seeking insight on the following:

That the person that completes the form also gets a copy of the form via email, but without any admin (OFFICE?) stuff, so that the person can reply to the email with file attachments or other correspondence...

In includes\modules\pages\my_page\header_php.php, after the line:
zen_mail(STORE_NAME, SEND_TO_ADDRESS, EMAIL_SUBJECT, $email_text, $email . ' ' . $lastname, $firstname, array('EMAIL_MESSAGE_HTML' => $email_html), 'my_page');

I propose to insert something like:
zen_mail($person_name, $person_email, $email_subject, $email_textX, SEND_TO_DEPT_ADDRESS . ' ' . STORE_DEPT_NAME, array('EMAIL_MESSAGE_HTML' => $email_html), 'my_page');

but with the following manipulations:
$person_name = $namefirst . ' ' . $namelast;
$person_email = $email
$email_subject = $work_id . ' ' . $work_title (where work_id and $work_title are each limited/truncated to 32 chars max, thus 64 chars total)
$email_textX = form input (My Page Data Submission) less any admin (OFFICE?) stuff
SEND_TO_DEPT_ADDRESS = as defined in includes\languages\english\my_page.php
STORE_DEPT_NAME = as defined in includes\languages\english\my_page.php

However, I have yet to work out what the last parts of the line do ie:
array('EMAIL_MESSAGE_HTML' => $email_html) (I only want to send and receive plain text, no html, emails)
'my_page'

Nor these lines located just above the proposed insertion
$email_text = zen_output_string_protected($email_text);
$email_html = nl2br("\n" . $email_text);

Thanks in advance.