Re: essential cookies
"With it in mind I propose that cookie banners are in fact not necessary at all: everything that is essential in this sense can be done with session cookies which are not restricted by the EU cookie law (1) at all since that only requires consent for cookies *stored* on user equipment and session cookies by definition aren't."
Firstly ePrivacy/PECR does not require cookie banners at all! Banners are the mechanism of (some) websites to inform about the cookies and to obtain the consent for them that PECR mandates.
Secondly, session cookies *are* stored (i.e. in memory), otherwise how could a session cookie by sent back to a website after it was initially presented to the browser. "Stored" does not imply some form of "permanent" storage (i.e. on disk), a cookie stored in memory is still stored, the duration of storage is not important. Therefore session cookies are treated the same as "normal" cookies with regard to PECR.