for the ebv,
the two pipes which enter it together, on a standard car, run from the turbo compressor and the actuator.
the 'top', solitary, pipe runs back into the inlet and recirculates air which has been bled off.
so, if the ebv is 'open' and there is nothing on the two pipes at the bottom (because you now have a prv) 'technically' unfiltered and unmetered air can now enter the induction system.
this could potentially lead to bits of crap like grit and dust getting into the induction system and going into/ through the turbo (not good) or the ecu marginally underfuelling, as there will be more air than the ecu thinks there is (also not good)
practically speaking, with the small amount of air going through there, this is unlikely to have any significant effect. However with turbos spinning at silly high RPM any crap in there wont help.
If you follow the solitary top hose from the ebv back to the induction system, cut it off (leaving about an inch or so) and then plug the hose with a small 10mm bolt or maybe 8mm or whatever is a tight fit you can now remove the ebv, or just leave it in place safe in the knowledge that everything is tickety boo.