First AG brew coming up and I have some final questions...

At this point, I have read and re-read Palmer and I have decided to make switch over to AG, cuz I just want to make it that much more fun to brew.
I have a good to great deal of confidence in my process from all the reading, but the recipe building process and more specifically what each grain adds as far as fermentables and how that affects abv vs taste and that sort of stuff.

Buddy and I have decided to brew a burly brown ale that has a high 5 or preferably 6% abv.
I picked up a good recipe from Beersmith and off we go.

Grain bill is:
9# 2-row US
1# Caramel Malt 80L 6-row
0.5# Choc. Malt [350]
0.5# Special Roast [50]

1.5oz. EK Goldings (60)
0.25 tsp Irish Moss (10)
0.5oz EK Goldings (2)

At this point in the process of learning, my first question is:
1) What part of the bill gives it the higher abv potential? and Why?

The grains are providing the ppg like an extract.. yes, but what fermentables are giving it the abv boost and taste?

2) I have a package of Notty that expires 2/2013 and my experiences is that it is more suitable because with VT weather this time of year, my ferm temps will be 60's if I use a blanket or insulation.
Would i need 2 pkgs? (Recipe called for White Labs- California Ale btw)

3) Will 11# of grain fit into my 5 gal cooler with 3.5gallons of water?

I'll take a crack for you...
1 - Your 2-row base malt is where you're going to get most of your fermentable sugars and thus your ABV potential. The 2# of other malts you have will have some fermentable sugars, but they are primarily for the flavor.

2 - If you're concerned about the viability of your yeast (and really, even if you're not) make a yeast starter. If it kicks off strong and really starts to floculate, then you're golden. If it is slow, you may have to boost it a few times, but you'll get off the ground and have something ready to pitch. If it doesn't kick off at all, well you've only wasted a yeast starter and not a whole batch.

3 - It's going to be very tight, if it fits at all. I've done 11# in a 10gal cooler and had plenty of room, but I'd guess it was more than half full.

Good luck!
-Kevin

To get higher ABV use more base malts and mash on lower temperatures (around 145-150F).

Pitching rate depends on OG and volume, for ale's it is usual to pitch 750millions of cells / ml of wort / Plato degree. You can calculate it by yourself or use calculator like yeastcalc.com.

Rackers have great calculator for how big MLT you need:
http://www.rackers.org/calcs.shtml