The word مرال means شکار یا بز کوہی. There are two words: رویا which means growing and روءیا which means vision or dream.

In the arabic language, the pluaral of non-human plurals is always feminine. This is a grammatical rule of the language. Ex. Beit is house, which is refered to as "He" i.e. Hua Beitun -- It is a house or literaly, he is a house, whereas for it's plural it is Buyut, for which we use the feminine pronoun i.e. Hiya buyutun -- They are houses or literaly, she is houses.
Similarly, Malak or Melek in arabic is Angel and masculine -- and Malaika or Melaika is Angels and feminine. And I can't think of any reason for it to be makrooh - Our prophet (s.w) has commanded us to name our children with beautiful names, so certainly to name a daughter after one of Allah's great creations seems fine.

There is no reason for it to be makrooh. But isn't ملک a kind of male name? Although I see some people name their daughters 'malaikah' ملائکہ. This is just the plural of Malak.