Two things: 1. Discuss location limitations with the bride and make sure you have this in your contract (the Clients confirm they are aware of location limitations for photography). Clients need to have reasonable expectations. The location is their choice and they need to discuss this stuff with coordinators, priests, etc. They can expect certain shots from the back but they should not be expecting say low right angle shots from the first row, or side shots, etc. These are the limitations of the location which they picked, so they need to have a good understanding of this stuff before the wedding day.
2. Scout the location and have a chat with the priest. Speculating regarding lenses before that is really pointless.
Also, when i work with limited movement situations, I do bring primes but having zooms is a must.
30 minutes for formals is not enough. By the time everyone gets out of the church, all hugs and kisses, etc, etc and you will have 15 minutes left. Are you doing formals right next to the church? Are you doing formals of the wedding party or family shots? Family shots take longer. Well posed formals take longer. What if the weather is bad and you need to drive to an indoor location? Talk to the priest and maybe he will allow posed wedding party shots inside the church with the flash after the ceremony is done. More importantly - discuss this with the bride so she has a clue of the impact of time limitations.
Planning is the key, especially if you are just starting with weddings.
Good luck!