It may seems strange that a background character like Lieutenant Oicunn is in sameway connect with Battlefront II but there is a connection between the Imperial offecier and the events told in the videogame's "Campaign Mode".

According to the Expanded Universe Oicunn achieved "the position of Admiral and the honor of becoming a clone template for future stormtrooper ranks.".
At the end of the mission "Kamino : changing of the guard" the retried Clone Trooper says that after the so called "Clone Rebellion on Kamino" the Empire started to use new clone templates for his army: this new templete is Oicunn, at least one of them if the Empire used other templetes.
The two sources of the Expanded Universe

So , even if not expressly, Oicunn is mentioned in Star Wars Battlefront II and it is possible the stormtrooper of the Original Trilogy have been created from his "genetic material" according to the EU, even if the two sources, Canon and EU, are not incompatible in that case ; but this is another story ...

May the Force be with You