Would it be possible to have a quick scene maybe after the council scene where Obi wan overhears a conversation between qui gon and dooku? You wouldn’t even really have to see them, they could be on another side of a wall or something. And Obi wan is just overhearing. Theres gotta be phantom menace footage of Obi wan walking and then standing around looking concerned that could be rotoscoped onto a new background.
And both Liam Neeson and Christopher Lee have a wide enough body of work to pull dialogue from. I imagine there’s quite a bit of useful dialogue you could pull from hobbit/lotr.