Upon inspecting with a hex editor it seems that the files are just CGFX files with extra header data. You can cut the header from them with any hex editor (cut to the CGFX) and then just open the .cgfx in Ohana3DS.
You can do this with vgmtoolbox and this plugin I threw together. Place the xml file in \plugins\AdvancedCutter and then load Nintendo DS - CAT Files into VGMToolbox > Misc. Tools > Extraction Tools > Generic > Advanced Cutter/Offset Finder, then just drag in all the files to cut them.
ndsscat.zip (Size: 526 bytes / Downloads: 53)
(showing that it works)
You can do this with vgmtoolbox and this plugin I threw together. Place the xml file in \plugins\AdvancedCutter and then load Nintendo DS - CAT Files into VGMToolbox > Misc. Tools > Extraction Tools > Generic > Advanced Cutter/Offset Finder, then just drag in all the files to cut them.
ndsscat.zip (Size: 526 bytes / Downloads: 53)
(showing that it works)