First, right now I have 30XP from before getting card. I am supposed to get 60XP....still 10XP under silver. If I add my wife as a cardholder, do we get another 60XP to our family plan bringing us into SILVER?
XPs are collected per individual/member. There is no "family" XP and not shared between family members.
Not sure if additional cardholder will even receive the bonus XP, especially if you add her after the approval.
In my case during the previous 100XP promotion period, it did but it was clearly stated so in the promotion T&C, and I had added her during the application.
Do we have to book the flights with this card, or can I book with another card and still get the REGULAR and ACCELERATED miles? Do these miles post only after we fly and if we become SILVER after booking the tickets but before flying, do we get the higher accelerated miles?
You will get accelerated miles no matter how you choose to pay, as long as you hold the card. They are posted at the same time as regular miles which is after completing the flight.
Accelerated miles rate is the same across all statuses (5 per Euro).
For the regular miles, you will earn the amount based on your status at the time of the flight, not booking.