For the repo sync issue, can you follow the recommended fix in bug  crbug.com/824915 .

The Hook script is failing because you repo is not up-to-date, you local branch is missing the config respect_server_db. It should be fixed after you run repo sync. 

Still the same issue: https://paste.googleplex.com/6251536116088832

Did you also follow the step in comment 17? You shouldn't have seen this in the log:
fatal: unable to access 'https://android.googlesource.com/platform/external/libcxxabi/': The requested URL returned error: 400

This means you still cannot access the android code base.

Still the same issue unfortunately unless I'm doing it wrong.

What did you do? This fix is just to generate the new android credentails and remove the old one. 

I copied the script as instructed and pasted it into the shell

1. Only Run sth like that in your script:
tr , \\t <<\__END__ >>~/.gitcookies
.googlesource.com,TRUE,/,TRUE,2147483647,o,git-modia.google.com=1/Dz_TRHhHv-YPmLlqCpIvgSv6ql2r-24Wi9rP4D8y4VM
__END__

2. vi ~/.gitcookie
Remove the old .googlesource.com xxxx credentails.

For the hook script error in https://paste.googleplex.com/5078096659087360
You could run below command as a workaround
sudo apt-get install hiera-eyaml

Am I removing the android.googlesource.com ?

https://paste.googleplex.com/4707661534724096

File another ticket for the hook script issue crbug.com/826520.

re #9. Yes, please remove all entries of android.googlesource.com. I saw there are at least two entries in your cookies. BTW, there are also two entries for android-review.googlesource.com. I suggest you remove all of them and generate a new one.