I just checked today in-person and I can confirm what's listed on this map (https://www.seattle.gov/documents/Departments/SDOT/TransitProgram/Rainier%20Ave%20S%20Bus-Only%20Lane/Rainier_Transit_Map.pdf) reflects the current on-the-ground status.

I have already updated Rainier Avenue South to include cycleways and bus lanes from S Edmunds St to MLK Jr Way S. Would appreciate a quick look from a experienced mapper (https://www.openstreetmap.org/changeset/177915190).

On a related note, it looks like someone has already updated portions of Rainier north of MLK. However the current tagging for cycleways is on both sides. I know there isn't a bike/bus lane on the west side, but haven't touched this part in case I am misunderstanding the tagging.