Change the squid port:
config setprop squid TCPPort <portnumber>
However, this may break transparent proxy mode unless you also do this:
config setprop squid TCPProxyPort=80:<portnumber>
And since the current value is 3128 for this, too, I'd suggest:
config setprop squid TransparentPort=<portnumber>
And finally, to activate your changes:
expand-template /etc/squid/squid.conf
/etc/init.d/signal-event squid restart
Creating samba shares
I think you just need to create "ibays". I believe that ibays are published as samba shares using the permissions you specify when you create them.
Caveats & Excuses
I have not personally tested the above settings, but I don't see why they wouldn't work. Having said that, I seem to make a lot of posts that require subsequent fine-tuning...