Hi there! Nope, "ya tengo muchas hambres" is not properly said. "hambre" like "hungry" i think, is an uncountable thing so you can't put it in plural. To say that would be something like "I have many hungrys/hungries" or whatever way it would be typed down in case it would be possible. Maybe if you want to answer that you are really hungry you could say something like "Me estoy muriendo de hambre" --> something like "I'm dying of hungry"

if you are a human with 3 or 4 stomachs... you can!!

You just say. Tengo mucha hambre Ya me dio hambre Ya me dio mucha hambre Me muero de hambre Tengo tanta hambre que me comeria un caballo, etc

no. correct is: ya tengo mucha hambre.

Yes, you can say "muchas hambres", but is just poetic and archaic.