Seeed XIAO I2C and SPI

I want to know if there are any issues using a 3.3v processor to communicate via I2C (wire) to a 5v powered 3 -MCP 23017 and 4 - PCF8574 extended I/Os? Do I pullup the SCL,SDA lines to 3.3v?
Also I am using a W5500 Ethernet shield, does it have to run on 3.3v?

For I2C you need a bidirectional level shifter.

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Thanks,
just bought the level shifter.
I haven't done the PCB design yet, other projects need to be done first.
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