Would most of this stretch of King even need transit priority signals? It would only be streetcars going straight through the intersections.
Yes and no. Even though I'm an avid cyclist, I question the wisdom of allowing bikes to go straight through. I foresee problems, for cyclists, motor vehicles and streetcar clear running. But by saying that as a cyclist, I also apply that to taxis, who shouldn't have an exemption, even if it is only certain times.
Edit to Add: For cyclists, the safest and most logical procedure would be to dismount and walk across as a pedestrian, at least until such time as road users are aware of the flows at the intersections. I emphasis, I'm a fit and avid cyclist, so this isn't pandering to Mary Poppins and ting-a-ling cyclists. It's because I know drivers aren't going to be looking and this is going to be pandemonium initially. As a pedestrian crossing, you're still not safe, but sight-lines and protocol are much more clearly established. Frankly I'd not chance cycling through unless there's no traffic, it's just not worth the risk, even if you have clear right of way. One idiot driver coming too close, suddenly you have to deflect and get caught in the tracks, and....
There's one and one priority only at this time for this project: Give the streetcars priority of motion. Cyclists should dismount and cross, and that way *all* vehicles save for streetcars (and idiot taxi exemptions) must turn allowing streetcars clear right of way since turning cars won't be blocked by cyclists flying through on the inside curb.
One further thought on cyclists allowed through running at intersections: If it is allowed, it should be by a signal phase with pedestrians, both cyclists and pedestrians are at risk at the same time from turning vehicles, so it makes sense to protect both with the same signal phase which would not interfere with streetcar clearance if timed to allow the turning vehicles to clear the intersection first.