ツインサソリの手裏剣
Tsuinsasori no shuriken
'Twin tigers' is双子のトラ (futago no tora) in Japanese.
Possibly Futago no Tamashii Futago - (a) twin Tamashii - Soul
Imōto no futago no imōto
双子の猫 = futago no neko
I don't speak Japanese fluently, but my guess is 'kawaii sasori'. Kawaii being the thing you shout when you see something cute, and Sasori being the Japanese name for scorpion. If Cute Scorpion was supposed to be a word then I have no idea sorry. What I answered was just what you would say if you saw a scorpion and said "ah! A cute scorpion!" "Ah! Kawaii sasori-chan!" ('-chan' is just what you could put on the end of sasori to make it sound cuter I guess. It isn't needed but if you do find a cute scorpion, I would add it).
i would say a scorpion because they are bigger
You may say 'futago no kumo,' written: 双子の雲
escorpião
In Chinese, scorpion is translated as "蝎子" (xiēzi).
You could say futago no shimai, but the word for sister (or brother) would depend on whether you are talking about an older sister (onesan) or a younger one (imoto), and that goes for twins too, so you always know which one was born first. Futago is twin.
"Twin", as a noun, is singular; so, "twin is" is correct. "Twins" or "twin & _____" would be plural, in which case "are" would be correct.
I'd say a viper.