If you don’t want the background to change at all you can do a couple of things.

Use the same combined image and then completely remove the CSS that changes the hover image. That will make it use the same top image. You could also create an one arrow image file and remove the CSS for the hover image. The one arrow image would create a smaller file which would be more efficient.

Thanks but how would I go about safely doing that?

Creating a new image file? That would require an image/picture editing program such as Photoshop.

I not get it to take any action upon hover, behave like the last breadcrumb

this might be easier if  you asked Brandon how much he would charge to just fix it for you…  this is fairly heavy customization…