Education verification on a background check?
It depends. Did they ask you for your GPA on the consent form? If not then no they will most likely not be able to recieve that information. I work for a background screening company and when we do education verifications we only ask for dates of attendence and degree obtained. Most universities will not release GPAs unless you expressly authorize them to release transcripts.
Will chase verify all of my previous employment?
It is unfortunate that you put down the exaggerated information on your resume. This makes it hard to skirt around the issue. If it had come up during the interview, and was in verbal form, perhaps the interviewer would not remember the exact details. You should never lie on your resume. Please go and change it now before you encounter another problem with other potential employers. If they call you to find out why the information on your resume differs from what they obtained, try to say that you made some typos in your resume and did not check it thoroughly - it still not a good thing, but better than saying that you falsified your resume.