也许 vs 或许 vs 可能 usage
see e.g.bkrs: 可能 might (happen)
possible
probable
possibility
probability
maybe
perhaps #170

也许 perhaps; probably; maybe #676 

或许 perhaps
maybe #2652

coclusion: 可能 unlike other 2 can be noun and includes ＂possible, possibility" ("literal" translation of 可能), can be used as adjective (see sample phrases with 可能的) 可能,也许 include "probably",或许 does not (lower degree of likelihood), also note frequency ranks with 可能 most frequent, much more at bkrs