I updated the doc a bit, but you can use price and event_seats too.
From the doc, I added:

For all possible fields, look at eme_events.php, function eme_new_event.
Many newer event options are stored in properties, see eme_events.php function eme_init_event_props(), for a whole list.

It is not that user friendly, I know (not my code initially), but I’m thinking about revamping the whole thing …

The directories mentioned don’t exist by default and you should create one. Best is to use
WP UPLOAD DIR/events-made-easy-frontend-submit/ (WP_UPLOAD_DIR is to be replaced by your wordpress upload directory location, typically it is wp-content/uploads/ )
Reason is that updating your theme won’t destroy it. Also changing it directly in the plugin subdir will cause it to be destroyed when the plugin updates.
Also make sure the webserver has access to the file/directory you created/changed, otherwise it won’t work of course.

On the dashboard, under the Send Mails menu option, the Select the Event(s) drop down option does not display all of the events. Only one event shows here instead of all of the events. How do I fix this issue? I’m guessing there is a setting somewhere or something but there are so many settings, I’m not sure which one correlates to this option. I’m trying to send an email to all WP users for a specific event but only one event out of about 6 show up in this Select the Events drop down option.