Again, too many to answer but here is an interesting article on one strain (there were more than one) of Shingon Pure Land thought, as conceived by a medieval master named Kakuban (pdf file):
This book by a Japanese Shingon priest is also highly recommend as a basic overview. It's also quite a bit more expensive than it was when I came across it in the early 1990s.:
As for the Huayan School, Shingon founder Kukai ranked the Huayan Scripture second-highest to his own esoteric scriptures, so he had respect for it. I don't know that one can speak of comparative cosmology between the two systems; Shingon thinks of reality in its own way and I can't do justice to the Shingon worldview in this kind of limited format.
" I would like to know the soteriological goal of Shingon.": Shingon speaks of Sokushin Jobutsu
, or "Buddahood in this very body." Through manipulation of body, speech, and mind (using mantras, mudras, visualizations, ritual implements, altar spaces, and mandalas), one can become one with a Buddha or Bodhisattva through ritual technique. Shingon also has rituals for more worldly goals. There are a large number of rituals, mandalas, and esoteric texts.