Remember, 880 has a considerably better suburban signal than 1010, so there could even be a simulcast if AM is of any future importance to the news outlet.
Not really. When a sale brought Infinity's KFWB into an excess station situation due to the Viacom purchase of KCAL_TV. KFWB, the considerably inferior signal, was put into a trust pending a future sale... which took quite a long time to occur. In the meantime, they implemented a less expensive talk format.
Prior to that, both KNX and KFWB were dividing about a 3 share of news listening, so it made no sense to continue having two news stations in the market.