We don't hear about any fighting in the Landreich, but that doesn't mean they were left alone - all it means is that WC4 took place elsewhere. Remember, at the end of False Colors, Tolwyn warns Bear about staying in Landreich. Also, supporting the Landreich's efforts to obtain a powerful Kilrathi fleet carrier could definitely fit into the general concept of creating new enemies for Confed to fight.
So, it may well be that nothing at all happened in the Landreich (an argument in favour of this view is the fact that Kruger was willing to lend some of his equipment to the Border Worlds, which he wouldn't be if the Landreich was in serious danger)... but it may be simply that we didn't hear about it because it wasn't really relevant to WC4's storyline.