Larisa - From Russian name Larisa which is in use in Arm since XX c. It comes from Greek laris "pleasant", "fragrant". The others connect this name with Greek laros "sea-gull". The diminutive forms are Laris, Lara.
Grigoryan - Grigorian or Grigoryan is an Armenian surname.
It is a patronym from the Armenian equivalent of Gregory and is the Eastern Armenian form of Krikorian.