Regarding PLC and several input/ output modules
Well, you could use a load cell multiplexer like this one: -

It uses an SPI bus to communicate with the host so, if your PLC can provide this, one multiplexer can get you 6 bridge input channels. These units can also be used with single-ended inputs to take the servo potentiometer signal (if you need that level of control).
You can probably find an SPI card like the above suitable for driving several servo motors too.
There is also the Microchip MCP3424EV demo board that can provide 4 channels and costs £16: -

Or build one yourself.