Where do you want to use that TESOL/TESL certification? If you want to teach in K-12, then work on a plan to graduate with as little debt as possible so that you can have more flexibility in where you look for your first teaching job. You also need to consider state certification rules, and where you might want to begin your career.
If the TESOL/TESL certification is not for K-12, and you plan to go abroad for work, then certification issues don’t enter into it immediately. However, as a TESOL professional myself, I recommend that you get state certification. It really will give you more flexibility over the long term. I came into the field as a career-changer, and my MS Ed TESOL without state teaching certification means that I can work in adult ed and pre-college Academic English programs (which I greatly prefer), but don’t have much of a chance of ever having full-time work with benefits where I live.
For your interests, there are advantages to the Delaware program because of the additional semester abroad. Do get more details about that. Is that first semester in a Spanish-only program, or are the classes conducted in English? What would your living situation be? Is it a home-stay where you would use Spanish in all of your free time, or would you be in an apartment or other residence with other US students?
Here is a nice calculator to help you and your family crunch your numbers: http://www.finaid.org/calculators/awardletter.phtml