Hello,

Just one thing: when a user writes cycleway=opposite_share_busway, they mean that in the "backward" direction cyclists may use the bus lane.
This tag does not convey any information about the "forward" direction.  (Which is incidently a very good reason to get rid of this tag.)

Instead of changing it into "cycleway=share_busway", I think "cycleway:left=share_busway" is a better option.  This is clearly the situation for this road.