Your plan looks really good, but I think you might be able to save in a few spots.
Your existing credit for "Perspectives on the World Christian Movement" should fill the non-us history/culture slot so you can avoid the spanish clep. Also the "exploration of nature and society" sounds an awful lot like an environmental science course, was it? That could potentially be your other science but for now I'll just move on assuming it isn't.
I see that you're planning the overlap between the upper levels, the basic requirements, and the liberal arts reqs well. So I get that removing the spanish clep would remove 6 credits you're planning to use for liberal arts. You've got 40 liberal arts right now, and with the 5 planned business ethics, analysis lit, nutrition, civil war, and the cornerstone would bring it to 55. You can take the two freebie fema courses IS 242 and IS 240 which are each worth one liberal arts credit. Taking you down to only needing one more 3 credit course which counts as liberal arts and you could pick that up anywhere.
BTW - Take the DSSTs soon, at least before the end of September. Then you'll qualify for the 'free retake' if you don't pass one.
http://getcollegecredit.com/assets/pdf/D...litary.pdf
Let me suggest a slight alternative to the path you have set (which works totally fine, btw).
The other day I spoke with someone at COSC who said the Shmoop Shakespeare course should come across as ENG 320: Shakespeare, which would make it a 3-in-one: upper level, liberal arts, and also filling the extra literature requirement from the general electives. Then you can swap out substance abuse for shakespeare at shmoop. That would fill out your last 3 credit course for liberal arts.
But if you're going to pay for a month of shmoop, you might as well take a few other things there... since it's one monthly fee for unlimited courses. So you could get Biology done there instead of taking the Nutrition TECEP. You could pick up any of their other liberal arts course instead of the "analyzing lit" since shakespeare would meet that specific requirement (and they have lots of general liberal arts to pick from in literature or maybe history). That would swap out the cost of a DSST, a CLEP, and a TECEP ($350'ish) for the $80-something cost of Shmoop.
You could save a bit on the business ethics course too if you take it from Davar (
http://www.davaracademy.com/business.html) because they're only $70, and COSC does bring that over as liberal arts upper level from there. Of course, the free retake on the DSST right now may be more valuable, depends on your perspective.
Leaving you with only 1 DSST left to take, the civil war course.
Another option would be to get at least 4 courses done from Straighterline so you qualify for the COSC tuition discount on your Capstone and Cornerstone.
http://www.straighterline.com/colleges/c...e-college/ It would cost more to take some of those at straighterline, and they wouldn't all fill the spots (no upper levels from SL to COSC), but you'd have to assess whether or not the cost of doing that saves more in the overall tuition later.