The Cyrillic alphabet is closely based on the Greek alphabet. Under Peter the Great, the forms of letters were simplified, with some appropriate only to Greek being removed. Further unnecessary letters were expunged in 1918, leaving the alphabet as it is found on p. 200 of World Braille Usage (Russian).
Fita was derived from the Greet letter theta, Izhitsa was used to translate the Greek letter upsilon, and the dotted i, as well as yat or jat were letters of the Early Cyrillic alphabet. All of them are no longer part of the Cyrillic alphabet used today.
As these four symbols are not listed in World Braille Usage, if these symbols are merely listed, a transcribers note can explain their omission in braille. However, it they are used in a passage, send along that print sample and we'll look that over next.