I just asked my wife about her experience with Morden Blush and she said she hasn’t had any fungal issues and she doesn’t mulch them carefully. But they are, in fact, quite thorny. She has a John Davis too, with not very many thorns at all. It’s a lovely shrub rose:
http://www.highcountryroses.com/john-davis
For the ground you might want to consider a variety of thymes- they are happy with neglect and thrive when walked on. @Lordkiwi had some nice photos on the site just recently: