Having looked into this further, the MPI CSI 2 spec suggests using a dedicated bus for each device (camera). The addresses are fixed by the spec. From what I could understand from the Omnivision specs, the SCCB_E signal is indeed intended to act as an “enable” of sorts, which would allow placing multiple devices on one bus. The same result can be achieved using an I2C mux or an analog switch on the I2C lines. This would however require driver support, and I haven’t yet checked how open the drivers are (is the source available?).
Anyway, it makes much more sense to use one of the I2C buses available on the low-speed connector.
As to soldering, these are 0201 0Ω resistors, and while I don’t have the board in hand yet, photos seem to indicate there are several of those placed together right next to the high-speed connector. I’d say that is “precision soldering”. Anyway, even if precision wasn’t needed, the real problem is that in a product every board needs to go through soldering.