They're all Chaos kits, so it should look fine.

The
WE conversion is Forge World, right? Other than the obvious minor issue with having to superglue rather than plastic cement those parts, the only problem I could foresee would be those being designed for 30k Terminators rather than
40k ones. I used the
BA shoulderpads for some
40k Termies ok though, so chances are they should be compatible. Worst case scenario you might have to do some chopping and repositioning. Having to cut models to make them more Khorne-y surely only adds to their authenticity, though, right?