Hire a professional get several opinions. Check the expansion joint where the new foundation ties into the old. There are dozens of factors to be considered here so chose corrective action wisely remember you will never prevent the water from getting in prrmanantly. the object is to minimize...
Please don't plane your door. It's not it's fault. Check the hinges Adjust the frame this usually can be done with a hammer and a small piece of a 2x4. Gently tapping the 2x4 will move enough to allow the door to close. Check for settlement cracks and make sure doors are being used not abused...