Who's Coming to My High School Reunion?

It seems that a 50th high school reunion is planned for folks in Ukiah, California. What an event indeed! 

"And who's also coming to the reunion?," asked Lewis. With a crafty smile, dear Mack replied: "One grandfather, one grandmother, two fathers, two mothers, four children, three grandchildren, one brother, two sisters, two sons, two daughters, one father-in-law, one mother-in-law, and one daughter-in-law. But don't worry about the small space we've provided, for not as many people will attend as it sounds. By the way, Lewis, in addition to others who are attending,
how many people will there be from what I said, and who will they be?"

Somewhat puzzled, Lewis hesitates, and asks you, his patrons, for some help. Please provide your reasoned answer below, as you help out our dear friend Lewis!

From Mack's reply, describe who is also coming, and how many will there be?

 Please share your thoughts, dear Coffeehouse patrons! Thank you, as your ideas are solicited... Please email your submitted replies here as we further critical thinking:
Ron Barnette, Zeno's Coffeehouse Proprietor

------------------------------------------------------------------------------------------------------------------------------------------------

For your ongoing enjoyment, I have retained these so-called Impossible Objects on here, as you contemplate the new challenge. I continually receive positive comments from many loyal Coffeehouse patrons. If you locate other good ones, please let me know. Please do this for our many visitors. Enjoy!...Ron Barnette

 

Some Impossible Objects

I credit Jim Loy for these marvelous example of so-called impossible objects, which should amuse you faithful Zeno's patrons, who appreciate thought-provoking stimulation. And further thanks go to Aaron Sloman, for this wonderful link to the Swedish artist Oscar Reutersvaard, who predates Penrose and Escher! 
 http://www.sandlotscience.com/EyeonIllusions/Reutersvard.htm

Freemish crate 1. Asymmetric crate. An M. C. Escher creation, I surmise
Penrose staircase 2. The Penrose staircase: Often drawn by M. C. Escher. Clockwise is downstairs forever.
tribar 3. The tribar: Another impossible object by R. Penrose. It's hard to know how to color it, as the interior becomes the exterior.
Penrose triangle 4. The Penrose triangle: Another famous impossible object by R. Penrose. This is sometimes called a tribar (see #3, above).
ambihelical hexnut 5. An ambiguous ring...What is the outside? The inside?