Make two arrays of structs in a BP, for example linear color and named curve value. Connect linear color to a ForEachLoopNode. Hovering over Array Element in the for loop node says Linear Color Structure. Disconnect it and connect the named curve value array. It says Named Curve Value Structure.
Now disconnect it again and connect the linear color array again. This time split the struct pin in the loop and you’ll get four floats: R, G, B and A. Now disconnect the array again. This is where things get weird. The float values stay in the for loop node instead of returning to the normal state of a gray element wildcard. Connect the named curved value array and you’ll say that the outputs don’t change, they’re still 4 float values for color. Even recombining the struct doesn’t help, you’ll get a Linear Color Structure output from a Named Curve Value input which probably isn’t going to work great.