It looks as if the MCP23017 is sold as a general purpose port expander for a wide range of 3.3v-5v platforms. Is there anything to be concerned about, if I use this with a T4.0?

For example the MCP23017-E/SO (randomly chosen variant at the top of a Google search) on Mouser is 16-bit, with a max speed of 1.7MHz. The T4.0 is 600MHz - the 1.7MHz max applies to I2C bus speed then? And 16 bits... the T4.0 is 32 bit. Again, I'm assuming these are specifications apply only to the bus, not the microcontroller itself?

Apologies if this sounds idiotic; I'd just rather not assume!