How would I add a link to the profile editing page of the dashboard?

I assume you mean /wp-admin/profile.php page and want to hide native password fields.

Try this (just test if form works ok with it):

add_filter( 'show_password_fields', 'modify_profile_password' );

function modify_profile_password( $show ) {

    ?>
    <tr id="password">
    <th>Change your password at</th>
    <td><a href="">password change page</a></td>
    </tr>
    <?php

    return false;
}