I have doubt on the id of the 2nd and 3rd bird.
On the 2nd bird, the primary projection is clearly shorter than the tail (only about 1/3) from the wing tip. On Acrtic, the typical ratio is 1 to 1. Also the head is a shade darker. So I would guess Pale-legged/Sakhalin Leaf Warbler. In Japan, it would be Sakhalin. The little hook at the tip of the upper mandible is not a clear field-mark of Arctic.
On the 3rd bird, the lower mandbile is all orange. I understand that the lower mandible of Arctic is even darker than normal in the breeding season. So I would go for Eastern Crowned.
HF Cheung
