A lot of somewhat well known people (not on the level of say President Obama or Justin Bieber obviously) have regular Facebook pages for their fans to friend and follow.
Mine are:
-John Ringo (right-wing Baen SF writer)
-Tom Kratman (ditto)
-Michael Z. Williamson (ditto)
-Bruce Barlett (political commentator)
A couple of former Olympic and world class athletes, nothing most folks would recognize. I don’t recognize any of the names in the OP.
SF authors S M Stirling and Eric Flint, a former MCPON (whom I actually know - he was COB on one of my boats), and a bunch of kidlit authors.
Ringo is the only name from the OP that I recognise.
I don’t, but a friend of mine has Dweezil and Ahmet Zappa and Eric Gilliland (producer of “Roseanne.”) She’s friends with them in real life too, I believe.
Prince is my Facebook friend. I’m pretty sure it’s him. 
My 14 year-old son is FB friends with most of the contestants on Hell’s Kitchen for the last few seasons. He regularly gets Gordon Ramsey as one of his “people you may know”.
One of my FB friends is a best selling author. His wife is even more well known as a nationally broadcast radio personality.
Another of my FB friends is apparently one of the all time greats of Magic: The Gathering
I’m friends with a couple of local (to Detroit) TV news people.
A DJ in a small town, an author who writes liberal books and does liberal research. That is about it.
I’m FB friends, and went to high school, with Kelly Corrigan, the author of several books. Here’s her wikipedia page.
I was at school with Stuart Braithwaite, guitarist with indie band Mogwai. I suppose he counts as somewhat famous, and he’s an FB friend.
A few that are well-known in their fields but no names the person on the street would recognize.
I don’t know if semi-famous even applies, but a Facebook friend of mine (and high school football teammate) won a Grammy for directing the Mumford and Sons video for “Big Easy Express” earlier this year.
Kristeen Young. She’s a St. Louis area singer/songwriter who works with the producer Tony Visconti and has collaborated with David Bowie. I don’t know her personally, but became familiar with her because she’s been Morrissey’s opening act on and off since 2006.
I’m friends with a number of moderately well known actors and comedians.
I’m friends w/ a few somewhat famous comedians/actors/musicians. A few of them are actual friends or acquaintances and others are just people I’m “friends” with to follow what they’re doing.
The singer of a band that has recently become moderately well known. I’m not really a great judge of that, but it’s possible to hear them currently on a pop type radio station, so I feel that’s fairly successful?
Anyway, we went to college together. He has a personal FB that is for friends, and I think it’s private (as in, it wouldn’t come up in a search of his name), and it pre-dates his involvement in the band. He has another one for fans.
Quite a few well-known SF authors and artists. Some include
Adam-Troy Castro
Bob Eggleton
Gardner Dozois
Peter David
David Gerrold
Norman Spinrad
Steve Miller/Sharon Lee
Terry Pratchett
Jane Yolen
(Many of these I’ve met IRL).
If you’re just talking about a famous person having a facebook page (in the technical, facebook sense of that word), then big deal, anyone can ‘like’ a famous person’s facebook page.
It seems rather you should be asking whether anyone is facebook friends with a famous person; that is, that famous person has a facebook account, just like yours, and they are your facebook friend, just like your buddy from high school is your facebook friend.
Me: Kira Roessler (basist for Black Flag, dos)
Brendan Canty (drummer for Fugazi, Rites of Spring)
Mike Watt (bassist for Minutemen, fIREHOSE, others)
Janel Laidman - famous in the knitting world for her fantastic sock patterns. I checked her out on FB and she didn’t have a fan page, so I sent a straight up friend request and she accepted.
I’m friends with a couple of local DJs, but since we used to work together, I don’t know if that counts as “Facebook friends”.
Also, I’m online friends (14+ yrs, pre-dating Facebook) with the wife of Jacek Duda, Polish basketball player famous in the 80s for leaving the national team while they touring the US. We only just haven’t met because they live on the east coast and we are in CA.
Not sure if any but the first one really count as “Facebook friends” with “semi-famous” people.
I’m friends with several people that are fairly big in the tabletop/miniature game world, but it’s a small world with a relatively small customer base, so they likely aren’t well known outside of that.