｡( ☆｡☆) ｡ Uninhabited Paradise

From the first list you must absolutely read:

Maurice by E. M. Forster
Kiss of the Spider Woman by Manuel Puig
The Memoirs of Hadrian by Marguerite Yourcenar
The Man Who Fell in Love with the Moon by Tom Spanbauer

And from the second one I'd recommend:

Mysterious Skin by Scott Heim
Forbidden Colors by Yukio Mishima
Dream Boy by Jim Grimsley

Aaaand books that aren't listed there but are definitely among my fave in this genre:

At Swim, Two Boys by Jamie O'Neill
The Carnivorous Lamb by Agustin Gomez-Arcos
The World of Normal Boys by K. M. Soehnlein

I'll stop here for now, but when you're done with these books feel free to ask for even more recs ;)