$\mathrm{Fe}{}^{2+}$ is titrated potentiometrically with $\mathrm{Ce}{}^{4+}$ using a platinum indicator electrode. Both couples are one-electron couples. Which statements are correct?

1. AThe equivalence point potential is the mean of the two formal potentials
2. BThe titration curve ($E$ versus volume of titrant) is symmetric about the equivalence point
3. CBefore the equivalence point the potential is controlled mainly by the $\mathrm{Ce}{}^{4+}/\mathrm{Ce}{}^{3+}$ couple
4. DFor equal $n$, the equivalence point potential does not depend on the initial concentration of $\mathrm{Fe}{}^{2+}$