After an entire day of fiddling with MV, PIXI, TexturePacker, Crunch and Powershell, I finally managed to get DXT textures loading in RPG Maker. They work in both .DDS (uncompressed) and .CRN (crunch compression) formats.
Only downside is crunch compression is lossy, so pixel art spritesheets don't look as nice, while .DDS looks perfect but the file size is quite a bit more than optimized PNGs.
My new RPG Maker music pack, Emotional: Redemption, is now in progress and will be coming to RPG Maker soon. It is an album that focuses on emotional themes including the darker forms of sorrow and despair. Below is a demo of a composition from the album.