IMO: I don’t think the odds are very high at all. I don’t think Brian’s remains would even be intact at this point if they were outdoors this long. I am thinking if it were Brian we would be talking about scattered / fragmented bones, and I got the impression these were closer to intact. One of the articles talked about “severe decomposition,” which to me implies that there was maybe at least a bit of other tissue besides bone, which I don’t think would be the case if it was Brian.
But possible? Yes I suppose so. At least more possible than any other finding I can recall in the last 15 years. Just unlikely IMO.
Also, only 1 of these 2 unrelated discoveries could be Brian. The other in the apartment building makes no sense (and I think was identified anyways).
Maybe I’ll be wrong. If so, at least that would provide some long sought after answers.