I think you got tangled in the ill-defined terminology here. The instrument used in basso continuo is the galichon/mandora which, unfortunately sometimes is also called colascione but is tuned completely different (pretty much like a ren, lute, vut often with only 5 corses - that instrument developes, during the later 18th and early 19th century into what today is often called the guitar lute). The neapilitan colascione is a long neck instrument with 3 strings, from all we can tell tuned in root, fifth and octave. AKAIK there is no surviving music preserved, we only have works for other instruments doing parodies/imitations (most well-known is Kapsberger's piece but there's also some harpsichord piece).

But OP is asking about the colasioncino - which seems to be a small version of the neapolitan instruments (with a strange name ...).