one or more technical issues

I think that there is a chance to get those accepted, if you refine your scanning/photographing skills. Your scans are out of focus, and I think that I see the same defects that @Jill_C sees and in my eyes, they are not introduced by the watercolour.

I agree with @Nancy OShea on the commercial value, and I doubt that you will generate many sales with such backgrounds.

In the first image there is a lot of digital noise, particularly in the darker areas. In the second image, you have blown highlights with a magenta hue in them. Similar issues in the third image.

I can easily make my own abstract images in Photoshop.  Why would I purchase them from a Stock agency?  Adobe Stock inventory already contains plenty of abstract backgrounds.  Stock customers come here in search of life-like images or drawings that represent real things they can use in commercial projects.   I just don't see much commercial value in any of these, sorry.