Sorry, I wasn't sure whether you were completely new to piggyhood, so I thought it would be better to give you some basic newbie info.
I had been wondering whether your first girl had some sheltie in her; she's certainly got the wide head!
If you want fun, you collect ideas and then have a poll on your shortlist of names.
Your peruvian girl looks a bit like an Allsorts or Liquorice me! The other girl a Dolly or another kind of sweet?
If you want to keep with the half precious stones, we have got an Onyx on here, or she could be a Tigereye ; and her sister could be an Opal or Moonstone.
Fluffy and Fairy?
It might be better if you settle the little girls first and then introduce them on neutral territory (run or bathroom floor with a big plate of grass or veg). If you could have them close to the others, or even where they can see each other would help with introductions. 10 days to three weeks; whenever it feels right.
Make sure that the hutch is thoroughly cleaned before you put them all back. Expect some bullying towards the new girls - they need to be firmly put in place first!