Filing PERM on L1B : Prevailing wages


I am currently on L1B VISA. I want to understand how PER filing is different for L1B under EB2 category from H1B VISA.

I have few queries regarding this.

  1. Is Prevailing Wage Determination(PWD) filing required for filing PERM under L1B ?

  2. What will happen if my salary is increased during PWD is filed/after approved ?

  3. Is it possible to transfer from L1B to H1B after PERM is filed but it(PERM) is not approved ? Will it affect the PERM approval ?