I have been wondering about this too, and asked about it some time ago, but I did not get a reply (about the sampling rate of the mod matrix, so I guess it is at the same rate as P12 and PRO2, which seems to be at about 11Khz or 22 because of Nyquist rates)
I am fairly certain though, that the oscillator signals are converted to digital because otherwise it would make one hell of a routing analog circuit when you have 32 different destinations slots... The oscillators are clearly digitized (they are available as sources for control purposes) , and these are then used to modulate the destinations. I bet each analog parameter like cutoff, osc pitch etc. Have one DAC associated with it, and that this one number holds the sum of all modulations done to it from various sources. I think the mod matrix would be very hard to do in the analog domain. Many destinations are both digital and analog in nature, and would not allow for connection without a bunch of convertion cucuits... If all is kept digital, and all control sources are converted to digital before entering the matrix, then all would be compatible in the digital domain all the way thru, untill an end modulation can be Delivered to any destination accessible, and those destinations being analog in nature only need to convert this number to analog before hitting the parameter.