Formally, they are included.
https://www.hilton.com/en/brands/sma...ry-hotels-slh/

Upgrades is going to be very finicky at SLH since many have a full hotel full of non standard rooms, and it may be difficult to rank them - one may have a balcony, but may be smaller than the room next door with a better bathroom but no balcony. I've noticed some properties have 20 room types for 30 bedrooms. So it's probably just as variable as the main brands, but in small hotels more difficult to deliver consistently. And even harder to deliver in a way that works for all guests.

Breakfast: many SLH have standardised breakfasts at all rates, you can't get a room only rate. In theory that means those below Gold are room only but I bet that never happens.