For this battle I would like a Gondor royal army of : swordsmen ,thrusting and parrying and swiping , Gondor royal cavalry (spear and sword, mounted officer fighting) and Gondor royal axemen , and an uruk army .
I think you might find a good selection of figures from the Pelennor fields. There are suppliers who can supply large forces at less expense but then,you get what you pay for. Quality will out they say and Mithril sets the pace quality wise. I don't think you'll find better.