  Scattering quantum bright solitons off barriers has been predicted to lead to
nonlocal quantum superpositions, in particular the NOON-state. The focus of
this paper lies on signatures of both high- and low-fidelity quantum
superposition states. We numerically demonstrate that a one-dimensional
geometry with the barrier potential situated in the middle of an additional -
experimentally typical - harmonic confinement gives rise to particularly
well-observable signatures. In the elastic scattering regime we investigate
signatures of NOON-states on the $N$-particle level within an effective
potential approach. We show that removing the barrier potential and
subsequently recombining both parts of the quantum superposition leads to a
high-contrast interference pattern in the center-of-mass coordinate for narrow
and broad potential barriers. We demonstrate that the presented signatures can
be used to clearly distinguish quantum superpositions states from statistical
mixtures and are sufficiently robust against experimentally relevant
excitations of the center-of-mass wave function to higher lying oscillator
states. For two-particle solitons we extend these considerations to
low-fidelity superposition states: even for strong deviations from the
two-particle NOON-state we find interference patterns with high contrast.
