Yes, Scarlet Leaves is definitely a goth band because most of their albums belong to the Darkwave and Ethereal Wave genres, which are among the core subgenres of goth music. Albums like Outlining States Of Mind, Deep Sad Frustration, and Compilation Of Early Dreams are examples of their goth sound.
Some of the other goth artists that are similar to them are Aenima, Mercury's Antennae, and The Palace Of Tears.
Scarlet Leaves is located in Brazil, São Paulo, active in 2003 — present. You can find more information about Scarlet Leaves on their GothDB band page.