Nope, you are wrong.

You can sell on the Ex-date and still get the dividend.

The entitlement date is just a formality and where the book keeping takes place. Ex-date will be the actual date of determination which is why the price will be adjusted on the ex-date.
There are always 3 dates in an announcement.

The only dates you should keep in mind is the EX-Date and the Payment date. The entitlement/lodgement date is just a formality announcement and does not affect you as a shareholder.

Nope.

Ex-date is the date you can start selling in the market and still get dividend.

Entitlement date or lodgement date or registrations date etc is the physical transfer of ownership of the shares where the previous owners name is strucked off and yours added. It matters little because it won't affect you as a shareholder expecting dividends. Although the names updated on the entitlement date will be used to decide who gets paid.