For a family wedding, I'd probably grab the seniority number and take the chance that somebody will work with you to get the time off.

For your own wedding,far better to defer the class date until after the honeymoon. Another possibility would be to pre-arrange the time off when you accept the job offer. You cannot be gone during ground school (FAA mandates x-number of hours) but they could build gaps between ground school/sim/IOE. That would still be far from ideal, most brides manage to make a wedding into a major production, with drama and everything. Too much distraction.

Actually, I would suggest deferring the wedding until after you complete IOE at your career-destination major airline...