Changing spelling of names

1. I spell my son’s name Muhammad Isma’eel- we pronounce the Isma’eel part as Isma-eel and use apostrpohe to so that its not pronounced “Is-smile” as most people say. Do we have to change the spelling of his name to Ismaeel?

2. My daughters name is Fathima Zahra and pronounced correctly as Faatimah Zahrah- do we need to change her spelling?

3. My 2nd daughter is Zayyanah? I was told it means beautiful. Is it a good name?
Jazakallah