I agree with David-A. OP (if his description of the facts is accurate, and I see no reason to believe otherwise) was denied boarding for an incorrect reason, he took all reasonable steps to demonstrate that the stated reason for refusal was wrong, he had a government document (passport) that was legitimately in his custody taken away from him without his consent (I am not talking about his initial handing-over, but the supervisor's refusal to return it to him upon request), and had intimate personal data (his passport information) collected without his consent on what may well have been a personal device.

If TIMATIC is wrong, that is not OP's fault. If easyjet choose to rely on an inaccurate reference source, or misinterpret it, that absolutely is easyjet's fault. If easyjet do not acknowledge EU261 compensation is due and pay it within the specified periods, OP should make a report to the UK Civil Aviation Department. I nany case, OP should ask easyjet for a written copy of his rights under EU261.

I would add here some awkward questions to ask of easyjet if they don't give a satisfactory response first time round:
* Is it SOP to refuse to return a passport to a customer after an IDB?
* Is it SOP to take copies of personal data on mobile devices?
* Was the mobile device used a personal or corporate one?
Oh, and if they deny that a photograph was made, insist that you observed the photograph being taken and ask them if they have had the device in question subjected to forensic examination to prove that the photograph in question was not simply deleted by the supervisor in question

Finally, OP, please keep copies of receipts for every single expense you incur as a result of this - right down to bus tickets and toothpaste.

If you wish to get aggressive, there are law firms and other claims managers that specialise in such matters. As a lawyer myself I am not going to recommend any particular firm, but here Google is your friend - try to find an organisation with a good record of mass claims. They will take a cut of your compensation, but IMHO you are very likely to get it.