I contacted Forest City, and they've told me that they are intending to have "seasonal tenant offerings" in these spots starting (hopefully) this year. There are 4 to 6 of these spaces (depending on how layouts and done), ranging from 366 to 506 square feet, and Forest City is anticipating they would be used for refreshment/light food sales and/or recreational equipment rentals--but they're open to discussing other uses. If you have your heart set on one (for perhaps a banana stand or some other offering), contact Brenda Temple at Forest City at (202) 496-6600.

Eventually the (currently naked) Lumber Storage Shed will be a retail pavilion, and later phases call for two additional retail buildings to be constructed just to the east of the shed (see the renderings way down at the bottom of my Yards Park page). And there will be ground-floor retail space at the Foundry Lofts just to the north of the park when that building opens later this year, not to mention 46,000 sq ft of retail space at the Boilermaker Shops.

UPDATE: Here are some more photos, from just after the fire was put out, from a neighbor across the alley.