Did the germans ever use Kontos like lances? Or what was their mounted soldiers main weapon other than the sword?
Light Cavalary: The main arnament of light german Cavallary was the Framea, a small Spear for throwing and melee. Tacically they filled the same role as mounted Peltasts, useing an cantabic-circle to throw their Framea-Javelins into the enemy rows. This was clearing the way for the Spearmen useing their Shieldwall (RTW's Spearband is correct), and Unit which had been turned to havoc by the light Cavallary was then easy bait for the strong Infantry. Incase of Need, the small Frameas were used as close-combat weapons but then the light Cav was knocked out to fast.

Noble Cavallary: Similar to the displayed "gothic" Cavallary the nobles were armored and used Lances primary and swords secondary. Realism diffrences between RTW and my Research isn't so strong.

Yeah, I know how hardy the Steppe ponies were. They actaully look a lot like those German ponies you showed, and I can see how they were such good horsemen, with the similar looking blood stocks. And I assume by a Zuegel you mean a bit and rein? Because I can't imagine to too many horsemen other than the horse skittish Romans actually needing their reins, espically the Steppe horse archers and the lancers who needed their two hands
The Germanics were originally composed of two diffrent peoples, the Indo-Germanen or "Aryans" (how the Nazis called them ) and the Megalith. Those "Aryans" lived in Caucasus and nowdays Iran, some tribes went of to Germany and others invaded India, the fate about the rest is unknown. Their Horses are the anchestors of Equus Germanicus, Scientists are sure their Horses were Equus przewalskii the mongol Horse.

Those Normadic Influence in their Ethnogenisis is the explaination why the germanics had such Horses and even went so far to have holy Horses for Oracles. The same Way the Magyars still kept their wild horses in the Puszta when they came to Europe. But with Time those traditions to breed Horses in the Wildbahnen died out in Germany and Hungary, the final strike against those Horses used for War were the arrogant Aristocraths in the Renaissance who claimed "they were too small".