@Spindizzy
 
Exactly.“Themed Names” were exactly the words I was looking for.Most of The Apple Family members have apple related names (Red Gala,Apple Fritter,Granny Smith),but that doesn’t mean they use apple as a surname or that they use surnames at all.
 
Same with the Cakes,Carrot Cake is the Husband of Cup Cake two types of pastry.Is not strange their kids ended up having cake related names.
 
I’ve seen some people wrongly using “The Sparkles” when referring to Twilight’s Family.Such thing doesn’t exist.Twilight Velvet and Shining Armor are proof of that.
 
And quite honestly,if they supposedly have surnames,why other ponies aren’t like that?
 
What about the single named names like Fluttershy and Rarity.Fluttershy’s name seems to be named based on her personalty and Rarity is definitely not “Rarity Belle” like some people believe.
 
What about Thunderlane and his brother Rumble?
 
What about the princesses? they don’t have surnames either.
 
In G3 Cheerilee was related to Scootaloo.No surnames.
 
Simply put,what the show staff have been doing all this time is following the same pattern of pony naming that has been used ever the franchise started: Simple words,usually related to the marks in their flank,the color scheme or personality.

@Amber  
What you say makes a lot of sense to me. Clan names and surnames would seem to be exceedingly rare in Equestria if they exist at all. They might work as we’ve seen so far, with extended family members having themed names, or having the same word worked into each given name.
 
It’s fun thinking about how these things come about in Equestrian society.

@Spindizzy
 
“The Pies” are still not confirmed since the names of Pinkie’s family (except for Granny Pie) are not revealed.Sure,we can use the prototypes Faust mentioned some time ago on Twitter,but even she said those names never caugh on nor approved.
 
However,clan names like “Apple Family”(along with the Cakes)is about as close we are going to get according to Nayuki,but they don’t have surnames.

@Amber  
Are we certain about that? Perhaps you’re right and “Macintosh Apple” is a bit silly, but I could swear that the phrase “Apple Family” has been used in the show, in addition to the Pie Family and Cake Family.

@Spindizzy
 
>Using Apple as a surname  
>Ponies having surnames
 
Stop it.Such things doesn’t exist here.

Big Macintosh Apple:
 
Brother  
Grandson  
Farmer  
Equestria’s Premier Origami Master

In this picture, there is a ship of paper and Big Macintosh.

“Eeeyup. Mah cootiecatcher is fabulous.”