Actually, at one point when I relocated and was without internet access at home for a 3 or 4 months, and I next signed in to Gmail, the last session's date and IP wasn't showing anymore. For sure Google knows, but it wasn't showing. Normally there is an option on bottom of the page showing the last session's date and IP, but apparently this is shown only for a limited amount of time, I'm curious how long.
Any idea on questions 1 and 2? As a writer I take intellectual property very seriously so I rather be sure (instead of assuming) before sending my writings to an editor through Gmail.