In Opera 12, you just enter about:config in the address bar. Then you scroll down until you find "User prefs" and expand it. The value you're looking for is "Hot list file V2" which is the location of where your bookmarks.adr file is located.
I think there is also a way to do it in the operaprefs.ini file, but I don't recall how.

Not sure about Chromra. Probably not possible, as Chrome is designed to be a "Download and go" browser. It's not very customizable.

I'm pretty sure the point of modern Opera is to piggy-back on Google's work and hope that the old Opera name can distinguish it from the thousands of other generic Chrome flavors. The only thing keeping Opera going is Opera-Mini. Which is pre-Chrome-piggy-back work. Their Chrome piggy-backing has been pretty unsuccessful. If I want Chrome, may as well get the real thing. I have no real desire for Chrome's twin brother, attempting to cross-dress as Opera. I see your soft-ball sized bulge, and burly, hairy arms... you're not fooling anyone and it's actually just sad.

Maybe Vivaldi will be a pay browser ;p They're the original Opera people. Though that browser also feels an awful lot like Chrome, even if it isn't based off of it.