So, to be a truly grapefruity, I wanted this beer to be pink. Magic Hat says they use beet juice it to color their Wacko beer pink. In my case, I added just the liquid from canned beets. However, I added it too early in the boil and it seemed to just stain the lupulin glands. It didn't actually impart any flavor. So by all means, scratch the "beet juice." Last night I experimented with some pink food coloring and that's definitely going to work. So I'll add that at bottling.
Gelatin I use to clear up the beer. I've used it on the past couple beers I've made and they turned out darn clear. It's certainly optional.
I'm not well versed on different types of LME. I would use the lightest you can find if you want to make the color pink. Otherwise, I think about any pale/light malt extract would be fine. Note that the 7 lbs. I quoted above is for DME. For LME, you'd need a bit more.