No gender for the name plutonium. All English nouns are of common gender.
Ismail is a male gender name, even it is not an Arabic name but you can change it to female gender name, Ismaila.
I assume you mean neutered or spayed. I would name it based on the gender it was born with, or with a non-gender specific name, like "Fuzzball".
The gender of the name "Gakonga" is not explicitly specified. It may be a unisex or gender-neutral name, or it may be from a culture where gender-specific names are less common.
Sexist
male
The name of Uganda's Minister of Gender, Labor and Social Development is Mary Karoro Okurut.
The name of Uganda's State Minister for Gender and Culture is Lukia Isanga Nakadama.
You can name a dragon on dragon cave before or after you find out what gender it is; it doesn't really matter when.
It's a boy's name
"Londres" is typically a gender-neutral name and can be used for both boys and girls. It is not commonly associated with a specific gender.
There is no specific name for the feminine gender of the butterfly. They are simply called females. The other gender is known just as males.