We discovered that we could add a 65 square foot walk-in closet to Lael's room for about an additional $1500, so at an incremental $25 per square foot we decided to go for it. The space beneath the mudroom was planned as an insulated crawlspace, so it made sense to dig to a full depth foundation and increase the house square footage.
The footings for the rear stairs and the back deck were also dug out as the additional foundation space was done, so that will allow us to proceed with framing starting this Friday! They'll pour the footings and the slab after the lower level is covered, so weather shouldn't hold that up as it did the foundation walls.
Below you can see the section of the foundation that was left open for access to the walk-in closet and the excavated area for the rear deck and stair footings. They say we're close to one of the points when progress happens with impressive speed, which we'll be very happy to witness given the plodding pace it feels like they've been making so far...