Ooooh, I really like that name.

He is now Kotkoti.

You could name her Betise, (pronouced sort of like "Betty's") which is a french candy, originally mint flavored with a band of caramel around them. The candy was actually made by accident, which is why it was given the name Betise, as it means "stupid mistake". Of course, as your nephini is a Peppermint Twist nephini, most will probably get that it's named after the candy. They aren't traditional mint colors, but they are still mints. Here's a picture:

Or you could name her Starlight, after a certain type of mint.
Sorry, tried to use the correct accents, and the site deleted letters. Had to edit some back in, minus the accents. Sorry!
P.S, if you're curious, the accent that got removed looked like this > only it pointed upwards. It was over the e in "betise". I'd show you, but it'd just get deleted again.

I've been thinking about this boy, Misty's brother--

Songbreeze, are you familiar with the children's book Misty of Chincoteague? Though the events are fictional, Misty was a real Chincoteague pony. You could give your boy a name from the Misty books. Here's a list of male ponies' names. The ponies were either characters in the series or relatives of the RW Misty--

Foggy
Drizzle
Wings
Sea Star
Phantom Wings
Pied Piper
Sandpiper
Cloudy
Thunder
Cyclone
Chilly Rainstorm
Storm Cloud
Cloudburst
Windjammer
Phantom Rain

"Starlight Mint" would be a good name for a Peppermint Twist Nephini with Sun Armor or Nebula. I'll try to keep it in mind for the future.

However, "Betise" goes with her Stripes very well. I discovered online that, if you want to make certain people know you're definitely talking about the candy, you can use the term Betise de Cambrai. That shall be her name. Thanx, Seven!

The only symbol I know of that you can use in a pet's name is the apostrophe, but I can't substitute e-apostrophe for the e-circumflex that actually belongs in the word. Sigh.

Songbreeze, how about "Data Ghost" for this one?

I put this in another post

I don't know if you like names in other languages or not, but here are a few that mean mischievous:
Shejtan(Albanian)
Bihurri(Basque)
You could also name her:
Little Rascal
Sly Dog
I thought they would be good for her:

Thanks! For him, I've decided on Cyclone.
And for her, I used your suggestion to come up with Phantasm.

Possible names--
Sir Mephisto Pheles (really, too obvious)
Lunar Corona Byakko

I don't want to call her a dog, Wildcat; Puffadores aren't dogs, anymore than Zolnixies are foxes. But the "sly" part suits her just fine. I shall name her "Sly Rascal."