I'm glad you are taking the time to think things through. I agree that as a general purpose knife the 240mm is most useful, and a good place to start. I'll answer your questions in turn.
1. The Artifex 240 isn't out yet, though I think that'd probably be the perfect knife for me--any ETA on those?
I don't know when they will be available, but all of the Richmond knives have been so popular that I know that Richmond is doing everything possible to get make them available as soon as possible.
2. The CPM154 steel on the Addict 2 scares me a bit, since my sharpening skills are not great and it sounds like that particular steel is maybe not the easiest place to start. Should I be as worried as I am about sharpening the CPM154 steel? (As a side note, I saw there's a $20 tune-up sharpening available on the drop-down box, and if I get the CPM154 Addict, I'm totally planning to do that.)
CPM154 should scare you a bit, if you don't know how to sharpen. It is a beautiful stainless steel that holds and edge for a long time. Its just really difficult to sharpen. I have other CPM154 knives, and did not have the sharpening stones to do a good job sharpening CPM154, so I didn't like it much. I do like the Addict 2 in CPM154. If you go with the CPM154, as you say, you pay for the $20 sharpening, but make sure you order the Shapton Glass stones in 320, 1,000, and 4,000 grit. Also, Richmond knives provides one free sharpening for the price of postage. If you are going to use the knife for occasional home use, it might actually be a good choice, because you could easily go a year or two, maybe more, before you need a complete resharpening, as opposed to a few swipes on a honing rode, or a light sharpening on the Shapton 4K
3. Is AEB-L considerably easier to sharpen than CPM154?
4. Any ETA on the AEB-L Addicts? I read somewhere on a forum that they were in the works.
Although he hasn't said so, I do believe that if Richmond could, he would snap his fingers and have his entire line suddenly appear in AEB-L. Again, I think he's moving as quickly as possible on that. The only Richmond Knives gyuto currently available in AEB-L is the Laser, and I have to tell you, even though I prefer heavier and thicker knives, I can't helping loving the Laser. You can't go wrong by purchasing a 240mm Richmond Laser. It is a fantastic knife.
5. Regarding both the Addict 52100 and the Fujiwara, is a carbon steel knife is the right place to start for a novice for (not particularly hardcore) home kitchen use only?
Carbon steel is the best place for a beginner to start because you learn how to sharpen and care for a knife when you start with carbon. Based on your questions, the following setup would be what I would purchase to get started (remember, you have to sharpen all steel, whether carbon or stainless):
1) Purchase a carbon steel Tojiro Shirogami ITK 240mm Wa-Gyuto for $79.00 from Chef Knives to Go, available here: http://www.chefknivestogo.com/toshitk24wa.html
2) Purchase the Shapton Glass three stone set from Chef Knives to Go, available here: http://www.chefknivestogo.com/sh3pcset1k4k.html
3) Purchase the DMT Extra Extra Course Diamond Plate to use primarily as a lapping plate (and very rough stone if needed), available here: http://www.chefknivestogo.com/dmtextracoarse.html
4) Purchase the DMT non skid Mat to place the Shaptons on while sharpening, available here: http://www.chefknivestogo.com/dmtnonskidmat.html
5) Purchase a bottle of camellia oil, available here: http://www.chefknivestogo.com/tsoilst1.html
6) Purchase Murray Carter's Blade Sharpening Fundamentals", available here: http://www.chefknivestogo.com/blshfubymuca.html
You would then be set up to learn how to sharpen and care for your new 240mm gyuto. When you figure out how to sharpen, your New Tojiro Shirogami ITK gyuto will be the sharpest knife you've ever worked with. If you decide to move up to a more expensive knife, then you already have the basic sharpening tools and skills that you need to care for your knives.