When syn/blends hit the market, I for one, thought that they were 50/50 mix. Turns out, they're not even close. Although today, I beleive that a blend is an O.K. oil due to good refining and the latest ILSAC standards, I still don't think there is enough syn oil in the blend to make it worth it cost beyond regular dino oils.
I do beleive in mixing your own dino/syn to make your own blend. At least you'll know the % of syn oil that is in the mix. I also beleive that regular conventional(dino) motor oils today are better than ever before and may even rival full synthetic motor oils for at least a short oil change interval(OCI) ~5000 miles. Beyond that, it's anyones guess, or a used oil analysis(UOA) just how many miles a dino can go and still have a good report!
As-far-as the vehicle warranty goes, the OP needs to document the oil/filter changes should a engine warranty issue arise. Use the oil that meet the Chrysler spec and sleep well at night.
Also, even though the dealer oil change is only $8.00(a good price), they can't "require" you to change the oil with them at any point in time for any reason unless you signed something. Only then, would you be locked in to doing so. Under the warranty period, if the dealership "requires" that you use them or their oil/filter(or anything else for that matter), they have to by law, give it to you.
Maybe they "recomend" that you do the 1st OCI with them and not "require" it; that's different! But, the dealer can't "require" anything from you except that you pay for the car. But, during the warranty period, it's KMA!