"They read to me a book" is not english.
But you can campare it with Spanish: "Ellos me leen un libro"
No, sorry the word order in English is as above. They read me a book. or They read a book to me. or They are reading me a book. or They are reading a book to me.
I'm afraid the English needs to be: They read me a book. or They read a book to me. or They are reading me a book. or They are reading a book to me.
Indication of the used pronoun:
No, because the verb is in plural: (αυτοί/αυτές/αυτά) διαβάζουν, not (αυτός/αυτή/αυτό) διαβάζει.
I agree with buratovich on this: "They read to me a book" is English - perhaps a little more stilted than ordinary, but is perfectly good English, especially when we want to emphasize that they read it TO ME!
I am a native English speaker, born and bred in the UK, and honestly, it is not perfectly good English. Good English is, as you have just said, 'they read it TO ME' not 'they read to me IT'
That is incorrect word order in English which should be direct object then indirect object with to. So, sorry it is not acceptable.
Here are some relevant reliable links: Check this out for objects with to. - http://esl.fis.edu/grammar/rules/order.htm
Be sure to note the to object: https://www.scribbr.com/academic-writing/word-order-rules-in-english/
In addition, I am giving my reply from many years experience teaching English at all levels.