Me or I?

My daughter has just started English. In her new book I read the following
Who is in the garden?
All my friends and me.
After contacting the publisher I received the following answer In the case of the song, which is written in a very friendly, informal
register, the phrase "all my friends and me" is a colloquialism which
fits the rhyme and tune very naturally.
The editor also commented: The use of 'me' as a subject might therefore appear in everyday speech
in contexts such as in the opening to a telephone conversation, "Hi, Sue
is that you?"" Yes, it's me." Here the response "Yes, it's I", while
grammatically correct, would not sound natural. Nor is it something that
a native speaker would say in this context.

I have two questions:
1. In the example "all my friends and me" is the use of me acceptable? Is it acceptable to teach it before the custom use "all my friends and I"?
2. Is it true that no native speaker would use "it's I"? Even in "It's I who has to thank you" for example.
Thank you so much in advance for your help!