I just used Magos Model Editor for the Models and Adobe Photoshop CS2 for simple recolouring of the icons, but you can also use the Freeware GIMP, a very good drawing program, with nearly the same functions as PS.
The thing with the models was very easy.
The thing you have to know is that all those fire effects, glowing effects, star effects and much more are called generally Particle Emitters, which can be made in every colour you want. The flames at the Infernal are Particle Emitters, too.
Magos Model Editor is the perfect tool for editing and creating particle emitters.
For editing those, find the Infernal model at the MPQ Browser and open it.
Then go to Window -> Node Manager
The blue fields with a white arrow are Particle Emitters.
Double Click on them to edit them.
Then a window will appear with many fields with many numbers, for just recolouring, we can ignore those numbers. As you can see there are fields with colours. The infernal mainly has green or olive colour. When you click on those fields you can change the colour of the emitter, now choose different blue colours for the 3 colour fields. Then press okay and the emitter is recoloured, you have to do this with every emitter.
The infernal has also Geoset Anims, also called Animated Textures.
For editing the colour of those go to Window->Geoset Animation Manager.
There should be 9 Geoset Animations, double click on each and change the colour of all green Geoset Anims to blue. Don't change the white Geoset anims.
After you've done this with all emitters and geoset anims, the model is finished and you can save it. You will get an error, if you don't put ".mdx" behind your filename, when you save.
For recolouring the icons, open Magos, go to the MPQ Browser, click on File, choose war3.mpq, then open folders "Replacable Textures" -> "Command Buttons" then find the button of the Infernal (BTNInfernal.blp), double click on it and Magos will show it you, then go to Window->Texture Manager and rightclick on the only texture, then choose Export and put .tga behind the filename.
Then open the .tga file in Photoshop or GIMP and recolour it.
(In Photoshop, use the Hue/Saturation edit.
When you recoloured it to blue, save as .tga again, or just hit save.
Then we need another tool, called WC3Viewer, with which we can re-convert the .tga to .blp (the Warcraft format).
Then you need to do the same with the DISBTN, which you find under Replacable Textures->CommandButtonsDisabled-> DISBTNInfernal.
