Normally, if you go in your hikashop cart module's hikashop options, you should have the option "show quantity" which, if activated will display the number of items automatically.
If you want to change the quantity of items in the shopping cart via the cart module, you should turn off the mini cart option and use the normal cart layout which allows you to change the quantity for each product in it.
For your last point, you can try to edit the file listing_img_title of the view product via the menu Display->Views and change the code:
<a href="<?php echo $link;?>" title="<?php echo $this->escape($this->row->product_name); ?>">
<?php }
echo $this->image->display(@$this->row->file_path,false,$this->escape($this->row->product_name));
if($this->params->get('link_to_product_page',1)){ ?>
</a>
to:
<?php echo $this->image->display(@$this->row->file_path,true,@$this->row->file_name,'id="hikashop_main_image" style="margin-top:10px;margin-bottom:10px;display:inline-block;vertical-align:middle"','id="hikashop_main_image_link"'); ?>