Consulate appointment for H4 before marriage

[n_sankara]

Hi friends,

I am getting married in april. I want to block the appointment date now.

1.Can I block the appointment date for my to-be-wife?
2.What details I need to enter in D156 & D157 about spouse?

I am working for an MNC, they are saying I need to block the appointment through BEP program only. My organization don't want to block the date till I get married. It will be very late.

3.Is it mandatory to block the appointments through BEP?
4.Can I block the appointment date on my own?

Waiting for the reply....