Hello Kalil
The Dynamic IP address should be no problem. This just means you should use a DNS entry as opposed to the IP.
I do believe you need to configure 'less secure' app in google. Since you want to use authentication as opposed to the new token based approach. Depending on your google account this might or might not be possible but would be a google limitation. I know the Analyzer Development team for instance uses Google SMTP as one of the test. So it should work just fine.
https://support.google.com/accounts/answer/6010255?hl=en&sjid=8455428319674893807-EU
Regards
William