I2C multiplexing with SDA only
Assuming your mux leaves SDA high-Z on unselected segments and you have a pull-up on each segment, the unselected targets will not see the start condition and will ignore the transaction.
Note that this all assumes that you never enable more than one segment at a time. Since each segment must be pulled up, enabling multiple segments may parallel too many pull-up resistors.
So yes, you can mux SDA and send SCL to all of your sensors.