Your issue is a serious leak. The water building up over time has caused the cracks and the leaks. I recommend to you to dig it and wash it as u stated and apply a role on seeler. I also would use the same material they now use on newer home wich is a black concrete vapour barrier. It will give your foundation a fighting chance. Doing all this with your drainage tile, stone will do the job. If you want to make extra sure and want to be able to remove any water sitting the re that won't drain, you can have all your drainage run to a low point with a pipe coming up to your finish grade ( large enough to fit a pump into). If you look into it you can find metal removable lids for these pipes so if cut to the right elevation, wouldn't be a havard and be barelly noticable. Hope that helps.