1. Not sure about Nexus as I haven't used one. But Samsung offers a Google-Free experience on their phones should you want it. You could use the phones without even registering/activating a Google account on it. My sister used her Galaxy Fit for two weeks before I started to wonder why she wasn't able to download any games at all (which was because the phone was not associated with a Google account). Without any Google activation, they won't even know that the phone you own is already out of the box AFAIK
2. Contacts could be saved into a phone only memory which does not sync to Google. I know HTC, Motorola, Sony and Samsung has this option, but not sure about your Nexus.
Basically, I could factory reset my Samsung devices, and on startup skip the Google activation and just use the phone. I can still get many apps from legit sources like Samsung's own AppStore for Android, and Amazon. That's probably as Google free as you can get: No Google service running at all with your login.