Do not think so
The merger of the London Stock Exchange and the Boerse should give us a first look at how post-Brexit financial markets will work.
Nope, because the politics card has not been played yet. It is still "yet another corporate acquisition" at this point in time.
Sure, the merger cannot be stopped at present and the systems can go to London as UK has not invoked article 50 and officially is still a Eu member which cannot be discriminated against.
How this will pan out after article 50 is invoked is in "God only knows" territory.