No, but the EU and US regulators will look at the Uk's reasoning for blocking the bid and it may influence their own decisions.
No. It's only relevant in the UK. If other regulators want to go forward with it then they can.
That's not how it works. Companies with global presence (like these 2) need to have regulatory permission in every jurisdiction where they operate. If a jurisdiction forbids the merger then they would no longer be able to operate there.
Consequently any regulator in charge of a sufficiently important market has de-facto veto power globally.
And if anything I don't expect EU regulators to be more lenient than the British ones.
Have the Commission approved this takeover, or have they just not made a decision yet?
Because it could just be a matter of the CMA being the first to say no...