Two CS547A sensors can be wired directly to one CR1000. One A547 interface is needed for each sensor, unless a multiplexer is used. A multiplexer switches all sensors through one A547 interface.
The CS547A instruction manual offers this warning: "Wire the conductivity excitation and temperature excitation lines in different excitation ports or measurement errors will occur. If multiple CS547A/A547s are wired to one data logger, each conductivity excitation must use a separate excitation port. However, you can wire multiple temperature excitation lines into the same excitation port."