Three little white flowers in Sikkim, 2017

[Claire Cockcroft]

After sorting through 1500 pictures and identifying most plants, I am puzzled by these three little white flowers.  I hope someone can help.  I feel like I should be able to recognize them.
Thank you!

"unknown-white-1" was seen in Gangtok.
"unknown-white-2 & -2-1" was seen near the Ringi River.  It had fuzzy yellow stamens.
"unknown-white-3 & 3-1" was seen near Lachung.

[Afloden]

The second and third images show Streptolirion volubile which is common at mid-elevations through the Himalaya into Vietnam and China. In Arunachal some of the forms had very well-marked leaves with dark brown-red chevrons.

The last two might be something in the Plantaginaceae, but I cannot figure it out at the moment.

[Claire Cockcroft]

Thank you.  Streptolirion volubile is not in any of my reference books -- which are few -- and is new to me.  Photos on the web show pretty dramatic leaves.  The one plant I saw had just plain leaves.
...Claire