I speculated briefly in another thread, but I wouldn't be surprised at all if DCA reopened before Disneyland. The park is already show ready, and I'd bet many kitchens are already cleaned and stocked for the food festival. Restocking merchandise in the shops shouldn't take to much time, which just leaves the attractions.
DCA has far fewer attractions, many of which are off the shelf- so the parts are more readily available and they take less CM's to staff. Also, quicker training for new CM's.
Fewer E tickets as well- Soarin', which is basically a theater so staffing is minimal and operation is simple. The most complex attraction is RSR, but it's new enough that I imagine it won't be to tough to get show ready.
It's the aging attractions over at Disneyland- Pirates, Mansion, Indy, Matterhorn- that are built on decades old tech and in many cases haven't been properly overhauled. Big Thunder is essentially a 2014 rollercoaster with a brand new track and computer system so it should be fine- Space is 2005, so also relatively new.
Splash is the biggest question mark- it's show quality was rough at best before it sat closed for a year, and with it's planned closure I wouldn't be surprised if they decided to just not reopen it. Or, operate it with barely any show elements working properly.