"psychics" type of activities are mostly about "souls"/etc long after the original death event. I don't yet know a good rationalization for that.

People have various ranges of abilities/sensitivities and i just theoretically allow for outliers like one or two orders of magnitude difference for some people (or a mutation producing for example something along the lines of that magnetic field vision that birds have (some molecule in their eyes acting like a compass))

OP probably chose the vague and general "[very sensitive to EM] people" exactly to avoid labeling.