I'd like to thank you for not giving up and help me try to troubleshoot my environment)
I've got it to work! I double MEM_LIMIT in .env file and all 3 nodes were able to come online and form the cluster 
Oh, I also bump my GCP instance type from e2-standard-8 to n2-standard-8 as well, instance have about 32GB and 30GB of memory respectively, I have few GB free, after running 3 nodes) which will be used by Linux Kernel, cache, etc...
Thanks again!