Whilst I might be stating the obvious here, it might be useful if we could identify the order of appearance of the different songs that use this or a similar chorus. Cazden et al in Folk Songs of the Catskills has a good go at this but doesn't manage to turn up any definite precedence.

I'll put in what I can from my own research and from Cazden.

Cazden gives the earliest appearance of 'The Knickerbocker Line' as 1859, however without a chorus. There can be no question or doubt that it is based in New York where the KL was a well-known wagon route. However, the song almost immediately appeared in Britain probably via the original performer touring, where several British adaptations soon emerged, with the usual chorus, sans 'Juber ju', the usual line being 'Watch her, twig her, pipe her how she goes.'

The 'Bigler' was built in 1866. See 'Windjammers'.

The Bodleian 'Grimsby Fishermen' broadside is very hard to date having no imprint. It is in with broadsides by Catnach and Such and could be anything from 1830 to 1880. The style I'd put at about 1860.

Unless anybody can come up with some more precise dating or a really intense comparative study of the earliest versions, it's going to be difficult to say which came first, second etc. My money at the moment is on TKL as being the original, but which came next out of the others is anybody's guess.

The Bodleian line goes 'Watch us, twig us, we're a popular juba jue' which I simply interpret as 'the bee's knees'.