Pin assignment

Both I2C interfaces are connected to pins via GPIO matrix, so you can select arbitrary IO pins for SDA and SCL.  You just need to observe the constraints of each pin such as I/O capability (GPIO34 – 39 are input only so not suited!), bootstrapping function. See the series datasheet for your device to confirm.

Pull up resistors

The ESP32 has internal pull up resistors which can be enabled. External may still be better though to allow a more exact resistance to be selected best suited for I2C?