The problem about "have got"

So,are they correct if i make the sentence like :

a. I've just got a fish (+ form)

b. I have'nt just got a fish (- form)

c. Have I just got a fish ? (? Form)

and i forgot, are they correct if i use the may+have got (for possessions)

examples:

a. He may have got a car

b. He may not have got a car

c. May He have got a car ?

are they correct,please fix these sentences if i am wrong.

and, I am sorry about that.