Hi Bunny,
2)The Klepper is not a sail boat, but I think it is a lot of fun to sail. I have a Klepper Expedition as well and find it quite entertaining to sail. My feeling is that learning to sail a kayak is not the easiest thing to do. But, if you can learn to sail a kayak, especially one with a full rig like the AII has, you're going to be able to sail just about anything.
a) The cockpit of the AII is quite large, I made a sailing board for the interior of my boat so I can move all around the cockpit and lean way out over the side to counter the wind in the sail. You don't need to make a floor like I have either. All you need to do is take the front seat out, maybe the rear, and put some foam or type IV PFDs in the bottom of the boat and you can move all over the place. I put the floor in because my knees didn't like hitting the ribs in the bottom of the boat. Check out the Sailing section in this forum...
b) The klepper sails wonderfully upwind.
c) A lot of people use outriggers and I plan to make a set for myself, but I have yet to use any. I sail on a lake with very gusty wind. Since I learned how to move around the cockpit and really lean out over the edges I haven't had a capsize. I'd like to have a set of outriggers that I can put out when conditions get to the point where you really can't afford a capsize. I have capsized a lot. It's kinda fun in the right environ. But in changing weather when you just want to get back home... or you really want to push the speed... why not take advantage of an outrigger. There's a company in Europe that has a very nice outrigger;
http://careen.eu/#/D/Home/. BSD makes a nice outrigger as well but it's even pricier.
Your friend is probably too used to being on a sailboat. A kayak will never be a sailboat. But, there is nothing greater for me than to see both my jib and main flying on my Klepper. Looks great, feels great, and it's fun! I recommend starting with just the jib. It will get you moving and is very forgiving. After a sail or two with the jib go out with just the main. It's going to catch a lot more wind but it's still very controllable. Remember, if you start catching too much wind just drop it, let the sheet fly and you'll straighten up and come to a stop. After a couple sails with the main put the two sails together and get ready to have some real fun. A canvas bucket works great for bailing the big stuff. You'll want a kayak pump when the level gets low. I just got a portable pump that runs on 3 D cells - I tried it today and it seems great. Learning to sail in a controlled safe environ is important. Because you will capsize and it's important to have the right space and time to recover from it. Wear your PFD, it can be tiring. It will be exhilarating as well though.
e) I have the standard rudder and find it works absolutely fine. A big part of sailing the Klepper is balancing the boat. I come about into the wind and jibe with the wind and have never felt like my rudder was lacking. Many reverse the rudder or weight them or extend them. I have never seen the need. Many canoe sailers don't even have a rudder. They steer the boat by careful placement of the lee boards and then proper weight distribution in the boat and a little tillering with the paddle. The key is to get out of the seat and move around the boat with the Klepper sailing rig.
There are quite a few sailors on this forum with quite a few different sailing rigs. Do a little reading in the sailing section. I'm not sure I'd want to recommend learning to sail the Klepper out in the Pacific. But if you have an nice lake, bay or pond to practice and learn on. I say go for it, it's great fun.
Dennis