Thank you to Katyusha on Foros Dinastias.
Princess Zenaida is sitting next to Grand Duchess Maria Alexandrovna. In the front row I believe it's Grand Duke Paul, unknown and Grand Duke Serge. Standing in the back is Grand Duchess Elizabeth next to Prince Felix.
Front row - left to right: GD Pavel, Prss Lyudmila Lobanova (lady-in-waiting of GDss Elizaveta), GD Sergei
Middle row - left to right: Zenaida, Duchess Marie of Edinburgh, Baronesse Anna Pillar von Pilkhau (Hofmeisterin of GDss Elizaveta)
Back row: Konstantin Balysniy (ADC of GD Sergei), Mikhail Stepanov (ADC of GD Sergei), Felix Soumarokov, GDss Elizaveta
This is July 1884 year, Ilinskoe.