Electronic – What are the options if the I2C slave addresses clash

First, don't use 0x00 and 0x01, those are reserved! Table 3 of the I2C Bus Specification lists the reserved addresses (and reasons why):

Slave addr  R/W        Description
 0000 000    0     General call address
 0000 000    1     START byte
 0000 001    X     CBUS address
 0000 010    X     Reserved for different bus format
 0000 011    X     Reserved for future purposes
 0000 1XX    X     Hs-mode master code
 1111 1XX    1     Device ID
 1111 0XX    X     10-bit slave addressing

You should also steer clear of 0x00 because that has no edge transitions, and might be an error condition (and it's hard to debug).

Other than that, I'd say "Just make it configurable." If you want to be able to plug in a wide variety of sensors, then you can either pay NXP for an address, or give it adjustable addresses. Software modifications should be obvious if you want to distribute the source code. A hardware option to toggle one or two bits of your selected address (solder jumpers on digital pins) is cheap and easy, or a ladder network of resistors with jumpers connected to an A/D pin could give you complete control in the hardware.

While not specifically the answer to your question, in a similar situation faced on one of our product upgrades, we used a workaround: An identically addressed I2C device needed to be added to the design, but conveniently the parts had Chip-Enable lines.

So the design simply added a CE off one of the controller GPIOs - actually we added 2, so that we could potentially stick in 2 more of the parts when inevitably the software team outgrows the additional 100% capacity we've just provided them.