I would use unfaced. I would buy as a roll (not precut batts) and cut you own 5 ft pieces.

Instead of trying to fill in all that space, consider insulating from the outside with 2 ins. of XPS or 4 ins. of EPS foam boards with a protective covering above-grade. First, assuming you can at least get some access, cover the soil in the crawlspace with a min. 6 mil poly. Don't get stuck! Here is a link that might be useful: Insulation

Your crawlspace should be vented to eliminate buildup of radon gas if you have a dirt floor crawlspace. Another option is to buy a radon blower kit. It comes with a radon sensor and if it tripps, it turns on a small blower fan that exhausts air through a small duct from your crawlspace.

yeah...Entergy is going to help you out! LOL! they do actually have a program in N.O. through Entergy using local energy raters. a little biased, but it is what it is. below is a copy & paste link to LSU AgCenter's study about insulating floors in homes with open crawlspaces. http://www.lsuagcenter.com/NR/rdonlyres/D33F711D-DC4B-4E4C-9ED6-A97DCE9DB026/79806/pub3187insulatingraisedfloorsHIGHRES.pdf I plan to insulate my floors with closed cell 3" everywhere...not average fill. once floor in bathroom is replaced and plumbing is finished. your biggest battle is going to be getting 3" everywhere, and not just averaged fill. plan to crawl under house before they leave. take a piece of wire with inches marked on it and a can of spray paint. have them come back and touch up low spots. knowing the foam companies you'll have to deal with, plan on double checking the work and not relying on their word that it is right. understand that closed cell is about R-7 per inch so 3" is R-21. actual R-values not quanitive values are what is important. best of luck.