I think the easy part would be coming up with a basic recipe for an IPA -- most IPA recipes follow a pretty simple malt bill as the hops are really the show. I'm guessing the goal here is to not create the most "knock your socks off" version of an IPA, but just a basic one that is more meant to show off the variations in flavor and aroma that different yeasts impart. A simple kit that has the basic IPA grain bill would be a Two Hearted clone recipe -- I believe Northern Brewer calls it "Dead Ringer". Anything with a basic 2-row base, and a little caramel malt to add some color/foam stability -- then the recipe would simply be hops and yeast after that. I also think that the Centennial hops used in that recipe would be appropriate for this project -- they are really flavorful and interesting, but won't try to steal the show that some of the more recent "hop bomb" varieties such as Citra, Mosaic, Simcoe, Amarillo etc. would.
As far as yeast strains, I would recommend going to White Labs website, when you search under their Yeast Bank you can choose a beer style and they list off all the options of yeasts for that style. When I hit the double IPA option about 19 different yeasts pop up. Everything from yeasts that would be classified as more traditional English style strains, to those that are now used a lot in the hazy East Coast IPAs, to everything in between (I see an Irish option in there as well). He could go really outside of the box and use a yeast that is traditionally used in other styles (Saison, for example), but it looks like there are sufficient options that fall into the IPA category of yeasts that he could make 6 different beers with sufficient variation based on the yeast profiles. At Stumptown, we use a very basic, neutral yeast strain for a lot of our IPAs and Pale Ales -- it would be the equivalent of the White Labs WLP060 American Ale yeast. This yeast does not contribute much when it comes to flavors so its clean profile allows the hops we use in the recipe to shine. However, when we do our East Coast hazy brews, we use yeasts such as WVP008 (East Coast Ale Yeast) and WLP066 (London Fog), and its amazing how different these turn out, not just in flavor and aroma (much more juicy) but also in appearance (very hazy, especially when dry hopped liberally).
So basically, just a simple recipe using basic malts and hops that won't take away from the intention of this experiment, then choosing six yeasts from options such as White Labs, trying to chose the yeasts that will be style appropriate, but yet different enough that he won't end up with six beers with a lot of them tasting basically the same. Hope that helps. I'd be glad to answer any questions, I love talking about beer. Cheers.