"Dll names should include UID".

Did not make my application failed. But it is a bit problematic. You should waste space by copying the same dll with different names for different applications.

Currently, this is just treated as a "recommended change", as it seems - but in the end it does make sense. [btw: just to clarify - this means the UID of the DLL, not of the package, so in theory the same DLL should contain the same UID name in each package.]

However, if there is a problem because you are copying multiple versions of the same DLL, this looks more like an indiciation that you should actually make it a Shared DLL, in an embedded SIS file of its own. Of course, you could also resolve this by giving each one a different UID, and having each application install a separate copy, but I believe this is not how it's meant to be.

* CON-02 / CON-03: "Failure to declare usage of network access or other services, often the submitter has declared some services used but not others" - "Ask user's permission before initiating a billable event"

I believe here the Symbian Signed criteria are not 100% clear as to what happens if the only type of billable events are one-shot SMS, specifically for license registration: if the user is told at registration time that an SMS is sent, does this need to be repeated in a privacy statement at the start of the application? In my view, it is actually more sensible to only warn the user when the charge is actually incurred, rather than at startup time when the user has no idea if they ever want to register the software.
You could say it does not hurt to warn more rather than less, but it may increase the risk of users blindly clicking "OK" on all privacy statements because they go, like, "yeah, I know...".

* CON-04: Backup and restore compliance is not met

Currently, there is still the ability to "opt out" of this, luckily, but testing is actually made artifically complex by the fact that you can't test backup/restore with software signed with a DevCert. So if you need DevCerts for the capabilities you are using, there is actually no way of testing prior to a signing attempt. Read here for the gory details:

http://developer.symbian.com/forum/thread.jspa?messageID=895&#895

(Nokia, please take note - this actually seems to be an installer bug on 3rd Edition :-))