I wanted to know what is and isn't true when it came to samurai fighting each other and ashigaru foot-soliders.
It's hard for me to answer this because I don't actually know what the common idea of samurai fighting is. Except two:
Samurai don't fight honourably in pairs during pitched battles, and they don't fight pitched battles only. All tricks, stratagems, and deceits are used, and none of this honour and loyalty only stuff paraded around.
At no point in history is the main combat arms of the samurai on the battlefield the sword. While swords were important, and good swordsmen celebrated, during the Sengoku the most common weapon was the polearm. So it's not weird that many of the famous fighters of the Sengoku used polearms, that warriors were depicted as using polearms, and that the title given to the first man to down an enemy in close combat is ichiban yari, or first spear (technically polearm).
If you have other questions about whether some depiction is accurate or not please tell me specifically which depiction.