I would take the pair of them at Newcastle in an instant.
Bosingwa would be an excellent mentor for Santon, he's played at the top level for years and we could get another two or three years out of him and then the position would be there for Santon to take over. Pardew let it slip last season that Santon wasn't a long term vision for him at left back, so if we could get Bosingwa for the right and one of the rumoured left backs we've been after (along with Douglas to bolster us in the centre) we'd certainly be cooking. Plus, if Danny Simpson is stalling on a contract then sell him for a couple of million and use that to go towards covering Bosingwa's wages.
Kalou or no Kalou we need to sign some non-African attacking players for when we lose Cisse and Ba (if both still here) to the ACoN. That would leave a front three of Best, Ameobi and Ben Arfa in the hole. Shola was like bambi on ice at the best of times, but now is so slow it's unbelievable. Nothing more than a hold up man when we're trying to keep a lead. Best has proved a lot of critics wrong since he's been here, but he still isn't the sort of striker that contributes much and is never going to be a prolific scorer for us. Kalou probably on big money so that'd likely be a stumbling block. He would fit in to our formation perfectly on the left though, would also allow us to rest Cisse and put Ba up front - we're going to have to give both chance to rest otherwise with the league, domestic cups, Europe and the ACoN they'll both be knackered by February.