I know it's been 7 months since I posted this, but I saw another thread asking about pepper additions, so I thought it would be worth posting results.
1) The dry stout recipe didn't turn out particularly well. This isn't necessarily the fault of AHS. I chose to use a different type of yeast because I wanted to collect it and use it for an imperial stout. I don't think the flavors imparted by the yeast went particularly well with the choice of grains. Basically this meant that I was starting with a mediocre beer, meaning that my experimental versions weren't likely to be exceptional either.
2) I added 1.5tsp of ground chipotle pepper and 1.5oz lactose to 1 cup water and added it to just under 3qts of the beer (after fermentation was complete). I let it sit for 2 weeks and then bottled. The pepper was pretty much overwhelming. It might be a decent beer with about 1/3 of what I added. That said, if you like really spicy things, this might work for you. The taste is okay, but it hits you in the back of your throat very quickly. 4oz is about all I'm willing to drink at a time.
3) This beer aged well. When I first cracked open a bottle about 3 weeks after bottling day, I couldn't stand it. I dumped the rest of the bottle after about two sips. After about 3-4 months though, it mellowed substantially. It's not great, but it's not horrible either.
I won't make this particular recipe again. I might try another small batch of pepper beer at some point in the future, but I'll need plenty of time to forget this batch first!