In order to be Muslim, one needs only the following:
- Belief in Allah
- Belief that Muhammad pbuh is His messenger.
Anything else is local/cultural/temporary/optional/open to discussion and thus will not and cannot be considered as a fundamental condition to make a Muslim a Muslim.
So one should check if they truly believe in Allah. And they are good for this life and the life hereafter.
Minaret or a rag/towel/topi/hat for someone’s head are trivial at best.