Sharia is a 6th Century legal system adjudicated by faith courts and enforced by religious police (or the secular police of your own Western country if you are unlucky enough to have a Government that has granted defacto power to Sharia courts like Britain has).
Laws must be passed by both the representatives and the senate, both of whom the people vote for.
Those laws are the legitimate laws of the country.
Those who practice Sharia are following laws that have not been passed by the Parliament. It should be banned on the grounds that it is treason. It is sedition. It is following the legal code of a foreign entity.
The Muslim Arbitration Tribunal has no powers to grant a divorce which is valid in English and Welsh law.[3][4] A talaq can be granted to recognise divorce.[3][4] A sharia marriage has no bearing on personal status under UK law.[5] The Muslim Arbitration Tribunal has no jurisdiction on criminal matters but can attempt reconciliation between spouses.
Sharia can not be changed, it is the unalterable law of Allah, perfect for every time and place, past present and future.
So it cannot be adapted. You must adapt to it.
That entity is not a foreign nation state though arguably with the reintroduction of the Caliphate by IS it could indeed be argued that it is the law of the Caliphate.
I honestly have no idea what you're trying to say here.
Iran is very much a theocracy where religious police patrol and where women are beaten for not wearing modest attire. It is not a Sunni theocracy but it is still an Islamist theocracy.