Bram,
Caspar, and Hawthorn are my favorite boy names from your list and feel appropriately autumnal. The fiery aspect of
Ignatius is neat, but there aren't any nicknames for it that I like.
I really like
Tamsin and have it on my favorites list.
Elva and
Fern are sweet. Their mythical/nature vibe make me think of an elf dwelling deep in the forest.
Beatrice is dignified while also being approachable and warm. If I were to create a character modelled on
Helga Hufflepuff, I would call her
Beatrice.
Chrysanthe - pretty