TECHNICALLY CORRECTED
ALL ISSUES ENCOUNTERED BY NOW SOLVED
WELL
After several nights, everything has been setup correctly.
Then issue that failed to clone private repository from github, was caused by incorrect "Windows Credentials" of github account. solvec by removing all github related credentials. https://stackoverflow.com/questions/51424051/git-clone-authentication-failed-for-url/62033875#62033875
The priority of environment variables in netlify is higher than the ones in global-data.js. so test in cypress is checking the data consistency on environment variables.