Sentences 2 and 4 are right.
In this context, I think that 'de' is only used in a negation and when you talk about quantity.
Je ne vois pas de lapins.
or
Je vois beaucoup de lapins
but not with numbers!
Je vois deux lapins
Note: A negation is not with 'de' when you use the verb 'être'. Then it's just
Je ne suis pas un lapin.