I don’t know about Android, but I do know that I already link my Facebook account with Windows Phone, so it wouldn’t surprise me. (Although Microsoft and Facebook do have more of a business relationship than Google and Facebook, so maybe not?)
I don’t know how typical this is accross other smart phone platforms (only had Windows) so I’ll just describe the basics of what I can do: I have both my email and Facebook linked to my phone, and so anyone I had an email address from (from any of my emails), and phone number, and a Facebook account, the compilation of all that information is meshed into one contact on my phone (and syncs with my email, IM account, Calendar (birthdays and events just pop up! quite nice), etc: Windows Live contacts instead of Google ones)... If your phone does have that option, it should be under some sort of “email+accounts” type option under a settings menu? That’s where my account-linking is, and there’s an option to add a Facebook account to the phone…
Now that I’m poking around at the options I have, I’m finding I can enter a lot of information about a person… (There’s even a ‘notes’ option!) but I don’t think that Facebook doesn’t do this specifically, and while my phone keeps up with my Facebook contacts, it doesn’t change or add information on my Facebook account. (On Facebook, all the information I have from people, they’ve provided. My phone is a blend of what I’ve accumulated of them and their own updating.) I can, however, message people and comment on and post things to Facebook directly from my phone.
And I know with Windows 8, there is further integration with your computer, and further integration between all the different places you interact with your contacts and schedule—it may do exactly what you want/need, (Pro version to run legacy applications), or there may be an equivalent out there currently/soon. Sorry for the semi-plug, I use more Microsoft products than anything else, so I know them more. Anyway, here, although I only scanned the page because I basically know already, is the promo Microsoft has about its People app. It’s basically an add, but it does highlight the larger things you can do with it. Hope this helps!