I still say shoot for Hyde-Addison for your two older kids. They will pull in your youngest for PK4 a year later with the sibling preference.
Meanwhile, your PK3 kid can get into Communikids, St Albans Early Childhood Center, or one of the other "community partners" that provide a PK3 education paid for by DCPS from 830am-3pm every day. The good thing about these centers is that you can optionally pay for before-care, after-care, school holiday coverage, and summer camp for your PK3 kid.
We currently have a PK4 at Hyde-Addison. It was a big scramble last summer to find care for our kid after PK3 ended in June at Hyde. The major summer camps in DC only go for 6 weeks because they mostly employ college students and graduating HS seniors. We had to scramble to find care for most of August - it was pretty rough for our kid. Had he done PK3 at a community partner, he would've had (paid) care all summer and transition smoothly into PK4 at Hyde.
Personally, I think Hyde now has the most desirable feeder pattern. Hardy MS is a lot smaller than Deal MS. And the new MacArthur HS in the Palisades is a lot smaller than JR and will have a higher performing student body by the time our kids go there in 10 years.
Good luck!