Does the Tacoma line have passing areas, that are just not shown on the map?
Yes, roughly half of it is double tracked to allow cars to pass each other.
And Park is only 4 lanes between Post St. (5 Pts) and downtown, the rest is a moderately wide 2-lane street.
The JTA alternatives don't show potential streetcar lines south of Five Points. All of their routes also have a huge one way loop in the Five Points area.
Might be enough room to put a single line track down the middle, and still leave one lane each way.
There's enough ROW on Park Street to run track between the existing road and sidewalks. Unfortunately, doing this would also remove a ton of parking for the small offices in that area. Personally, I'm not sold on running streetcar track down Park, south of Five Points. In my opinion, it would be a pretty expensive option because you would have to deal with a good amount of utility relocation. I prefer Oak, since it was an original streetcar line that's still lined with commercial and multi-family uses between Five Points and Park & King/St. Vincents.