Very sensible post and advice.
I will add:
- Never use the same account names (also email address for maximum security) unless you don't care they will be linked
- Add quotation marks in the Google search as it will then only search those words/numbers in the same order and not add its usually helpful algorithms. For example using a username on this site, search "rx8 racer" without quotations, and then with them to see the difference (warning: this will return UKP in Google search results for those needing to be discreet)
- Search mobile numbers with and without the space as one may produce hits and none on the other. For example "07123567890" and "07123 567890".