$2 sim and mbb

My phone is dual sim.

Q1. Can I use a phone sim in my phone as mbb only?

Q2. If I activate a $2 prepaid sim and recharge with $125 voucher will the double data apply?. Before all expiry dates obviously.

Q3. Can I use a phone sim in my mbb device(K5150), and do the same as Q2 above?

Q4. What is the definition of a new customer?

Thanks.