If subwoofer has DSP processing:
1) Should subwoofer DSP be enabled and used in combination with Audiolense measurments and corrections?
2) Should subwoofer DSP be disabled and Audiolense does everything?
My response would be "it depends". Is the internal DSP only for response correction (for the room), or does it also serve as protection for the driver of the sub? If the sub is ported (as most are), below the port resonance the cone motion is not controlled by the box, and putting power into it below that frequency not only does nothing for what you hear, it can damage the driver. If the internal DSP is used for driver protection, you do NOT want to disable that part of it.
As one example of practice, I'll use my studio monitor system. My mains are Mackie HR824, which have very accurate response and are good down to 40 Hz (the fundamental of the low E string on a bass). I wanted to extend this. I found a used EAW SB180 18" ported sub for cheap. I decided to drive it with a bridged Hafler P230, but the speaker specifies the use of processing. I bought a MiniDSP processor and a UMIK-1. I use REW for measurements, and crossover software in the MiniDSP. EAW says it is important to roll off the low end sharply below about 20 Hz or so to protect the driver, and recommends a specific boost around 30 Hz for driver response correction. I hand tailored the filters in the crossover (which I used ONLY for the sub, not for the mains), and tested the response with REW, tweaking and testing until I got the best result I could.
The point here is that if the processing in the sub is used for protection, and if it is decently adjustable, why not use it? If, however, you want to disable the internal DSP, make sure that anything you use instead is set up to do the needed driver protection with a high order (at least 4th order if not more) high pass filter set to match the box resonance frequency. Again, this is for a PORTED box. If the sub is a sealed box design, the LF protection is probably not necessary.
