We cannot really help you with your Maudio gear (we simply do not know it) but we can help you troubleshoot your Yamaha synths and preparing them to receive and respond to incoming MIDI signal.

MIDI works on a system of Transmit and Receive. There are 16 communication connections in a MIDI setup... identified as Channels.
They use “Channels” to hammer home the concept of tuning a device to receive data on a specific channel is similar to tuning a TV or radio to a specific channel. Easily understood - the data on channel 1 is discreet and is totally separate from the data on channel 2. Therefore, different instruments could be placed parallel to each other on their own discreet communication bus (channel).

For these experiments set your external controller to transmit on MIDI Channel 1.
Connect a 5-pin cable between the controller MIDI OUT) to the 5-pin MIDI IN of the Yamaha Synthesizer.

When you are certain that
1) your Maudio Keystation is set to 5-MIDI (not USB) — Very Important!
2) your Maudio Keystation is set to Transmit on Channel 1
3) the 5-pin cable is connected to the synth’s MIDI IN and it is set use MIDI
4) the synths are set to Receive on Channel 1 and are connected to a sound system

The CS1X predates USB (Yikes) make sure the switch on the back is set to MIDI. And this is probably the reason you are not getting any reaction from the CS1X — you must be sure your Keyboard is set to send MIDI, not USB.
CS1X Owner’s Manual page 42 on how to set MIDI Receive Channel
reface DX - Press [FUNCTION] three times and set the RV CH = 1

You can test the theory that the Keystation is the problem by testing the reface DX and CS1X — making sure they can trigger each other.

Using the MIDI breakout cable that came with the refaceDX, connect a cable to the one labeled “MIDI Out” to the “MIDI In” on the back panel of the CS1X (making sure the multi switch on the back panel is set to MIDI). Playing the refaceDX keys will cause the CS1X to sound (be sure to connect the audio outputs if the CS1X to a sound system) in this setup the CS1X will sound when you play the reface keys. If Local Control is On in the refaceDX it will also sound through its own audio outputs. If Local Control is Off, the refaceDX will not sound.

Try it the other way round, connect the MIDI Out of the CS1X to the MIDI In of the refaceDX. Match the Transmit/Receive Channels.
These tests will ensure you that your Yamaha Synths are behaving properly.

Computer... the reface can be connected to your computer with a standard USB (AB) cable. When you do so you must use a software application like Cubase, for example, to route the USB-MIDI messages between devices. You will need to have installed the “Yamaha USB-MIDI Driver” appropriate for your computer type.
The CS1X will require a MIDI Interface in order to connect to your computer (as mentioned, it pre-dates the USB system entirely).