It is NOT digital beamforming.This is digital beamforming in the Ku band range, which is 12 to 18Ghz. You got digital beamformer in 8 FPGA serving a 256 element array.
As simple as that.
And yes, the AESA vs PEASE is defined by the per element amplification of the signal.
By your definition if we swap the traweling wave tube on a PAC-1 to a solid state GaN amplifier network then it become AESA .