Acidic strength of diethyl malonate vs ethyl acetoacetate
The hydrogens which you have chosen are correct but both the carbanions are NOT eqaully stablised via the resonance. In case of malonic ester, the elctrophilicity of the carbonyl(c=o) is reduced due to the resonance from the oxygen beside it. So the carbanion will not be pulled very effectively into resonance as the carbonyl becomes electron rich due to the oxygen of the ester.

However, in the ethyl acetoacetae only one of the carbonyl groups is affected by this reasonace. The other one is still highly elctrophillic. So it stablises the carbanion even more. So it has a lower pka(more acidic) than the malonic ester.