Since we really know nothing at all about how the various barbarians dressed, nor how one group may have distinguished itself from another, they are conjectural.
I have made a number of assumptions in coming up with them:
First that wealthy Burgundian warriors on the west bank of the Rhine would have followed Roman fashion, just as most people in the world today follow Milan, Paris, London or New York.
Secondly that they would have had some sort of style of their own even if we do not know what that was.
Therefore I have depicted them in Roman style tunics with wide 2/4 length sleeves of the sort preserved in the Staetisches Museum Trier (which is admittedly of Egyptian origin).
I have assumed that they would have copied the Roman decorative clavi. The king's tunic is a direct copy of the decorative bands on the Trier tunic but I have given him a red rather than the un-dyed linen of the original. The other clavi are made up on the assumption that they would have perhaps copied the fashion but did so in their own way. The dead one has a straight lift from Roman styles, the other one standing in un-dyed tunic is a deliberate bastardisation. The other red tunic is copied from a reconstruction at the Musée des Temps Barbares in N. France which is conjectural and is an attempt to depict one step removed from Roman style but still following the fashion of the day.
The many surviving clavi and orbiculi (there is a fair selection in drawers at the British Museum) seem to show that the Romans themselves had a fair amount of variety in style and I suspect that how they were arranged was much a matter of individual choice, depending on wealth and sources of supply.
I have gone for red and white as the colours for no better reason than that was what the Romans favoured. I remember reading somewhere that green and red combination was favoured by both Goths and Franks but cannot recall where that comes from.The later Ashburnham Pentateuch shows various combinations of red and blue with some notables in green cloaks so I could perhaps have extended the colour palate.
The tunic worn over linen shirt may have been a fashion that came into being in the 5th C. Raffele D'Amato's Roman Militray Clothing (3) discusses this. The style is also reconstructed by R. Christen Die Alamannen and this was also the basis of the reconstructions at Musée des Temps Barbares. Of course there is no hard physical evidence for it so it may be entirely wrong!