Material Functions Won't append properly

[Icychopstix]

Currently working on a PPV Material, following this tutorial: https://www.youtube.com/watch?v=ldv94GUzTOA

I follow the tutorial exactly to this point, where you have to append the 4 material functions together. He uses the Append4Vector node, which I found doesn’t exist anymore but has the same function as AppendMany (or just stacking a bunch of append nodes). Despite all this, the output is a hard yellow. If I reorder the appends, it simply changes the color along the CMYK scale. How to I get it to output properly?

Most of the material function in question:

[Icychopstix]

Update: I think I discovered where exactly the problem is, you cannot append a float4 to a float4, so everything else is appending properly but it is just carrying the first color mask through