Do i really need to complete all the step by hand every time I "Finish" a branch and there is a conflict merging it with Git-Flow? Or there's a way to resume after all the conflict are solved?
After resolving the conflict, you simply call
git flow release finish [RELEASE_NAME]
again. git is 'smart' in that if you try to do merge from branch A to branch B more than once, the second and subsequent times are ignored with "Already up-to-date" as long as the source of the merge has not changed.