You've got the flash sorted which is good so I'd suggest using just one lens in the range of 18-70mm or so. Shooting weddings is tough enough without keep chopping and changing kit so I'd stick to one lens, know its limitations and work within them. You should still be able to get all the key shots, some better than others but I'm sure that'll be fine.
Failure to read thread/first post date!
Wedding already done and dusted!