Your /year /year/month pages are archive pages and these are exactly what h-feeds are for. A feed is a collection of entries and this is a collection of entries. A good use-case for having them as feeds wanting to follow people for a year or month only.
I really don’t see any reason for it not to be a feed and I’d argue for the sake of implementing spec and having tools that ‘just work’, it should be a feed.
I made an EP with some friends again, the music kind. It’s coming out on record, like vinyl. So hip, so cool. I wanted to make a record years ago and never did, so now I did. Go pre-order it in digitalis or vinyl form and give me some money, so we can afford to make #2 Solace Lane.