If I have you correctly, you now appear to be picturing a situation in which the radiation the geiger tube is seeing recently is from radioactive emitters attached to dust particles. These dust particles arrive in the neighbourhood of the tube by circuitous routes dominated by air currents. The ultimate source of the radioactivity is not known with certainty, but in the case of the radiation you saw yesterday it is unlikely to be associated with the woodpecker apparatus since it has been in a different room for several days. Any effects of the woodpecker itself would therefore be superimposed on this mystery source (probably radon).
Given what you now know, I wonder if you are now in a position to retrospectively rule anything out. For instance, can you now say that there does not appear to be any ionizing radiation arising directly from the woodpecker (i.e., radiation that travels in straight lines)? If so then I suppose this would leave open the possibility you have mentioned of some EVO-like entity that does not travel in straight lines like penetrating radiation but instead can drift around. Is there any way you can see to separate this sort of signal from a Radon-generated signal?
Final question -- one that I asked several days ago but maybe should be updated now -- do you think that the dustborne radiation signal you have now characterized so nicely fully accounts for the recurring fluctuations in background you were seeing last Fall?