Grammar

Hello, I have two questions related to the grammar in the following sentences.

If you answer my questions, I thank you for answering.

With the help of our guest, we’ll learn why teens tend to act before [thinking everything through/thinking through everything].

Q1: In the above sentence, I know that ‘thinking everything through’ is a correct expression.

But, I wonder if 'thinking through everything' is grammatically correct.

Q2: Scientists used to think that the brain was done growing by the time you turned 12 since the brain reaches its maximum size around that age.

In the above sentence, I wonder if I can paraphrase the expression ‘was done growing’ into the expression ‘was finished growing’ or ‘finished growing’.

Please reply.