Hi. I made an object for the EWI midi in. In my case it's for a EWI4000s. An EWI USB won't have the 'hold' and 'sustain' buttons.
Find it here: https://github.com/joaogatao/axoloti
It's pretty much what mtyas said. You can plug in the EWI and use custom midi keyb + bend and cc2 for breath. There are also other cc numbers for glide, the bend plates and the hold and sustain toggles (see EWI input tester patch). The bite sensor gives a vibrato-like pulse in the bend signal, but I haven't been able to get to the raw signal from the bite sensor.
For the object I tried to calibrate the glide and bend sensitivities, and made them adjustable in the patch so you don't have to fiddle with the calibration on your instrument.
I'm also 'copying' the EWI4000s internal synth, based on the Vyzex manual. It's a good learning school for ways to use a wind controller expressively. I hope to make some basic building blocks this way and use them with the axoloti's possibilities, rather than making a close emulation. This is ongoing work; more objects coming up, surely.
If anyone would take a look at the object and patches, I'm always interested to know where to improve and what other possibilities can be found for the EWI