Hi,
Looking at your screenshots, it seems you're using product / listing_img_title there. However, the best to know which view file to edit is to activate the "Display view files" setting in the Hikashop configuration which will display an red border around each view file on the frontend with the name of the view file being used to generate it.
Also, you need to make sure you're editing the view file for the correct template.
Finally, in product / listing_img_title, $this->element contains the information of the current category, not the information of the current product. The information of the current product is in $this->row
So if you want to display the content of a custom product field on a listing, the code should be:
<?php echo $this->row->xxx; ?>
where xxx is the column name of the custom field.
For your other question regarding the product details page. which view file to edit will depend on your settings. By default it should be show_default, but it might be show_tabular or another one. Again, you should use the "Display view files" setting to find out which one is used.