GIT Survey : 2nd Part

Considering the following local repository status, what set of commands allows to integrate the modifications from branch testB into branch master and to send these modifications to the remote repository ?

$ git branch -a
* featureA
  testB
  master
  remotes/origin/HEAD -> origin/master
  remotes/origin/master

To what set of commands is git pull equivalent ?
git fetch ; git rebase
git fetch ; git merge
git fetch ; git stash
git checkout -b master ; git fetch ; git merge origin/master
git checkout master ; git fetch ; git merge origin/master
No answer

What happens to lead to the following sequence ?

$ git add main.tex
$ git commit -m "Corrected typos"
$ git push
 ! [rejected] master -> master (non-fast-forward) 
[...]
$ git fetch
$ git rebase origin/master
$ git push
 ! [rejected] master -> master (non-fast-forward)
[...]

 

Considering the following repository, what are the different ways to identify the commit whose message is "Fixed Typo (again)"?

 faceb00c1516ood4465464651689834615164687 dparsons     2017-11-28-16:30:57 Updated Changelog (HEAD -> refs/heads/master, tag: refs/remotes/origin/master, refs/remotes/origin/HEAD)
 deadbeef01684986546549846468464651321651 sarias       2017-11-26-09:30:57 Removed Whisky taste, Fired Peter
 178761b91bd9cfa8413d88aea8344974835ceb1f dparsons     2017-11-26-08:37:05 (tag: refs/tags/v1.0) Fixed Typo (again)
 badc0ffee4bad5ea1f4846549877889131313216 peter_steven 2017-11-25-23:58:03 Added Uber-feature: Puppy can now make coffee
[...]
 0010101010101010101001010101001000000012 bender       1970-01-01-01:00:01 Big Bang (it seems)

 

2017-11-26-08:37:05
HEAD~~
HEAD~2
HEAD^
dparsons
HEAD^^
v0.1
(╯°□°)╯︵ ┻━┻
178761b91bd9cfa8413d88aea8344974835ceb1f
HEAD^2
178761b

Is it possible to associate to a tag a message that is different from that of the referenced commit ?
If so, how ?
If not, why ?