It is so difficult to know for sure where these are from. The seed bead colors all look like Antique Venetian (to Me), though not sure about the Orange Color or some of the Yellow. I cannot tell but are those big white beads glass and do they look German? (or perhaps Bone?). This is where it gets really hard when you cannot see up close and Personal..
I'm understanding the Nagaland attribution, however I would expect shell or coin closure. Yes they do loops w/beads too. I know I'm probably Wrong, but I'm getting Yoruba, (Yorubaland) or that general area, I think Nigeria.
I really would have to see the string- is it braided from the strands, what are the Large Beads like up close, what is the closure and stringing material like. While they don't exactly resemble the Typical Yoruba Ifa Divination necklaces with the bundles of seed beads through large beads, there is something about this that looks African assembled to me.

I would keep the Necklaces intact- maybe with repair. I think it's important to do so, and these are Nice!

Example from Bead Paradise- has Large White Hearts, though different design -same/similar Green seed beads.

More Pics Please, Good luck, Anne