The same as Google IME, except google has a evil virus-like secret upgrade popup.
Nope. See their FAQ https://support.google.com/ime/japanese/answer/166771?hl=ja which states otherwise.
edit: Found the "language" option on Google sign-in -- it's the scroller in the bottom right labelled "日本語". There's a small blue logo next to it that looks like the UN flag. Hope this helped someone.
edit #2: It's also in the URL, replace /intl/jp/ with /intl/en/ (for English)