I'm gonna be honest, all the "Why didn't OCR get a license, how stupid are they?" people are really pissing me off. Not least of which because it should be (and arguably is) legal to create derivative works, but because this applies equally to any other remix. Seriously, how many of you remixers have talked to Square-Enix or any other IP holder before submitting a remix?
If you think the fact that they were raising money off of this makes it somehow different, well, legally, you're incorrect. The law in many cases doesn't really differentiate between giving a way a derivative work or selling it. Add to that the fact that OCR holds fundraisers (which was exactly what this was) based on the love of the music on the site, and it means that this Kickstarter is exactly the same as all the other fundraisers (differing only in the tools used to offer it). So, anyone saying "OCR should have to get a license, the original artists should be respected," and yet isn't doing that for their own work or demanding that for the individual remix submissions is acting fairly hypocritically in my view. IMO, everything OCR has done is completely legal and above the board. Of course, "legal" doesn't mean you're immune from anything when dealing with a massive corporation.