How many confirmation do i have to wait before i can spend the inputs I already received? Can I spend Inputs with 0 confirmations?? If I could, are there some restrictions?
If the input is coinbase transaction, you can't spent it until it get 100 confirmations. Relevant code is here 
If the input is not a coinbase transaction, you can spend it by creating a raw transaction How To Create A Raw Transaction

However, receiving input with 0 confirmation is not recommended. 


  Zero-confirmation transaction vulnerability: accepting
  zero-confirmation transactions (transactions that have not yet been
  included in a block) from somebody you do not trust is still not
  recommended, because there will always be ways for attackers to
  double-spend zero-confirmation transactions. However, this release
  includes a bug fix that makes it a little bit more difficult for
  attackers to double-spend a certain type ("lockTime in the future") of
  zero-confirmation transaction.