Apparently, Topanga, Mrs. Svorski, and Auggie were mispronouncing the muffin in Mrs. Svorski's store. They pronounced it as Balochki when it should have been Bulochki. Bulochki is not a muffin it's a bun or a roll.
It's never explained how Riley was able to find or buy the hair coloring and at least two days worth of clothing to be able to dress up as a Harajuku girl without Cory and/or Topanga at least questioning her about it first.
Matryoshka dolls are seen in Mrs. Svorski's store. Matryoshka dolls are from Russia but Mrs. Svorski is from Ukraine.