Check out the counties online parcel map. https://scopi.snoco.org/ These are likely owned by the HOA. The houses around the streets seem to carry the same address as the existing roads. You obviously know the area better than me so if you think they are named streets, then according to the county, they would be named 121st Avenue Southeast and 122nd Avenue Southeast. I do tend to tag these as highway=service when I see them.
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