On Thu, 20 Mar 2014 21:50:43 -0400, Herman Miller <[log in to unmask]> wrote:

>Or the affricates could have been derived from palatals. */c/ > /ts/,
>*/ɟ/ > /dz/, and the absence of any /cʼ/ or /ʄ/ seems reasonable.

Eh, there's no particular reason that I know of for the palatal series to be likely to lack its ejective or implosive.  (Unless the velar series lacked its implosive also; then the palatal one could go along as part of a general constraint against back implosives.)

What ìs quite common, though, and perhaps useful to you, is for implosives to resist affrication.  So a series *[c J\_< J\] could evolve to [ts\) J\_< dz\)], whence the affricate members could become your [ts) dz)] with the latter resisting the voiced stop lenition, and [J\_<] > [J\] could be dealt with in some other way, like resolving to [j].