Shamim's Plugins

Yes, both are possible very easily.
Please go to Front End PM PRO > Settings > General then change “Editor Type” and “Allow Attachment”

No 1 & 2: You can wait for the next release as we already added a space there. Or you can add a space in https://github.com/shamim2883/front-end-pm/blob/25abae8891de1707324e54575eacbc3551a6eeca/templates/view-message-content.php#L53

No 5: You can wait for the next release as we already added a “s” there. Or you can add a “s” in https://github.com/shamim2883/front-end-pm/blob/25abae8891de1707324e54575eacbc3551a6eeca/includes/class-fep-form.php#L368

(Both in this plugin in your website’s copy)

For no 3 & 4: add following code in your theme’s (child theme’s if you are using) functions.php

add_filter( 'fep_filter_read_receipt_individual', function( $mgs_read, $mgs_participant ){
    return '<div class="fep-read-receipt-individual">' . sprintf( __( 'Read by %1$s on %2$s GMT', 'front-end-pm' ), fep_user_name( $mgs_participant ), get_date_from_gmt( date( 'Y-m-d H:i:s', $mgs_read ), get_option( 'date_format' ) . ' ' . get_option( 'time_format' ) ) ) . '</div>';
}, 10, 2 );

use following code

$args['participant_query'][] = array(
	'mgs_participant' => get_current_user_id(),
	'mgs_deleted' => false,
);

Try changing “Email Sending interval” to “15 Minutes” and “Emails send per interval” to 5. Then wait 15 minutes at least and refresh your website couple of times. Then see if it start sending.

Let me know.

To not generate an email for announcements please go to Dashboard > Front End PM PRO > Settings > Emails and then unchecked “Send email to all users of selected role(s) when a new announcement is published?”

Users can go to their settings page (from where they send message) and check if they want or do not want to receive email notification for message and announcements.

Do you use any custom code for this plugin in your website?