how is early access going to work?

[Dustytome]

also... 'Early Access' was marked in my MogStation but my 'Collector Edition' was not... despite ordering the CE Edition 100+ days earlier, anyone knows why?

As Rongway said, you need the full code that you'd enter at launch for the CE stuff. The pre-order code is just a generic code that is in no way specific to the variety of editions released. It's that 2nd code for the full license you receive that tells the system "This person bought CE, shovel these digital goodies into their mogmail."