Of those, only Rushden even starts to make sense.
Current population of Kibworth is under 6000. Desborough is 10,000.
Rushden is 30,000 - you could add Higham Ferrers (which borders Rushden) and that's another 7,000 and Irthlingborough with another 9000.
That's getting on for 50,000. You could put the platforms on the slows only and serve them with the Corby's - likely time penalty 3-5 minutes.
Or you could just have a bus linking Irthlingborough, Higham, Rushden and Irchester to Wellingborough station. Shouldn't take any more than 30 mins. That, plus the 6,000+ homes planned in Wellingborough (pushing Wellingborough's pop to at least 60,000) could result in quite a bit of growth.
why should Kettering and Wellingborough be left out of the the Nottingham and Sheffield timetable.
Whenever I travevel or my mum travels, we wait for an off an off peak south bound, always running late for ghost trains non stop from Leicester, then crowd onto an a 222
Indeed, just an hourly service to Leicester/Nottingham alongside the Corby stoppers will do.