\documentclass{article}
\usepackage{cmap}
\usepackage[utf8]{inputenc}
\usepackage[english,russian]{babel}

\usepackage[X2,T2A]{fontenc}
\DeclareTextSymbolDefault{\CYRYAT}{X2}
\DeclareTextSymbolDefault{\CYRIZH}{X2}
\DeclareTextSymbolDefault{\CYRII}{X2}

\DeclareTextSymbolDefault{\cyryat}{X2}
\DeclareTextSymbolDefault{\cyrizh}{X2}
\DeclareTextSymbolDefault{\cyrii}{X2}

\DeclareTextSymbolDefault{\CYRFITA}{X2}
\DeclareTextSymbolDefault{\cyrfita}{X2}
\DeclareTextSymbolDefault{\CYROTLD}{X2}
\DeclareTextSymbolDefault{\cyrotld}{X2}


% FITA, fita %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\DeclareUnicodeCharacter{0472}{\CYRFITA}
\DeclareUnicodeCharacter{0473}{\cyrfita}

\renewcommand\CYRFITA\CYROTLD %it is FITA, but fita glyph leads to crash...
\renewcommand\cyrfita\cyrotld %it is fita, but fita glyph leads to crash...


\begin{document}
ІЇЉЊђ іїљњћ ѢѲѴ ѣѳѵ

\Huge
\selectlanguage{russian}
Кернінгъ:

\selectlanguage{english}
\noindent{}%
Toilet$|$\\
Tiolet$|$

Ligatures: differ, definiton, difficult

\selectlanguage{russian}
\noindent{}%
Гой$|$\\
Гйо$|$\\
Гио$|$\\
Гбр$|$

1 Копѣйка

\noindent{}%
Гѵн$|$\\
Гнѵ$|$\\

\noindent{}%
Гѳн$|$\\
Гнѳ$|$

\noindent{}%
Тят$|$т.$|$\\
Ття$|$т{}.$|$
\end{document}