Wordpress Plugin modifications

Would like to make 2 small mods to a WP plugin I currently use for for my website http://playparkplus.co.uk

The website uses the Yachtzone theme of the Autozone template built by Templines , you can see official demo here:
http://preview.themeforest.net/item/autozone-car-dealer-wordpress-theme/full_screen_preview/15911085?_ga=2.158424698.1179639443.1585830642-1865023813.1585830642
One of the features of the Yachzone theme is a plugin used to add product listings; this plugin is called PixAutoDeal(pixad)

In order to have more control over my products in the backend I would like to make 2 small mods to the pixad plugin
1. to add an additional filtering field as an extra column in the product overview page of pixad plugin (see image attached). The field I would like to add will contain the seller company(manufacturer) information; this will help me filter and select only the products which belong to a particular manufacturer/seller
2. to add the option to publish/pending review in the bulk action box inside the same pixad plugin

What I want to achieve is to be able to temporarily suspend a range of products , for example all products by same manufacturer, by first sorting all products by manufacturer and then by selecting a bulk action publish/unpublish from the drop down menu

If there is another way I could achieve this without customizing pixad please let me know