Hey you can find information about switching here;
and
you can read about how people got on here;
No can answer this for sure how Banks do their fraud checks but Monzo have so many users on this forum and none of the regular users has faced this for no reason.
You and your wife will have to open individual accounts to get a joint account - At the moment Monzo are not offering joint accounts from the start or conversion of an individual account into a joint.