i saw a small metro bus, do they have a shuttle service to the trail head

Yes they do!! It's called the trailhead direct!

No

Actually, they’re taken over to the Bathroom

Yes, weekends and holidays April-October according to the info board at the trailhead. It starts from Mt. Baker Transit Center and has several stops in between. King County Metro operates it, their website should have a schedule.

Nope. But the walk instead bad