This post gives nice explanation about "We are all" vs. "We all are":
Both are grammatical, but the first is more usual. We are all is much more frequent than we all are in both the Corpus of Contemporary American English and in the British National Corpus. There are, however, some contexts where we all are would be used.
and gives this easy to understand example.
The answer to the question Who is responsible? might be We all are, and not We are all.
Could someone give more examples where "We all are" is suitable, since "We are all" is the default option?