Griff,
Welcome to the forum.
The WS477 switches are rated for 500 Watts incandescent. They are very capable of dimming your 3 incandescent light locations (sconce, large cans and small cans).
Your led lighting is a bit different. I'm assuming that this is currently plugged into a switched outlet. The problem here is that to do this "per code" you need a relay wall switch that can handle anything that might be plugged into that outlet. It also sounds like you prefer a toggle style switch. I'm at a bit of a loss to come up with a relay wall switch that meets those criteria.
If you have access to an unswitched outlet, you could try an appliance module (AM466). Unfortunately these devices incorporate what is know as local control or current sensing. There have been reports of problems (search the forum) when used with LED lights. They are very easy and inexpensive.
Another option might be a X10 controlled outlet. The X10 sr227 is rated for a full 15 amps and provides one X10 controlled outlet and one standard outlet. Unfortunately, these have the same local control feature. There are other manufacturers (Leviton) that make outlets without the local control feature. I have not personally used these. Another forum member may be able to help.
You mentioned scenes - scenes can be setup using a home automation controller (CM15a/ActiveHomePro) or using a "scene capable" switch. Scene capable switches are available from Leviton and Smwrthome but are rather expensive (X10 does not carry scene capable units). Since you already have the WS477 units, I'd suggest starting small and using the CM15a/AHP controller.
Using the CM15a/AHP you will be able to setup "macros" (turn off overhead cans, turn on led rope, dim sconce to 25%, etc) that can be "called" with your IR543. Your lights will dim/activate sequentially (not in unison) unless you program them to the same house/unit code and execute only one command (theater lighting dim to 30%).
Again, I don't have direct experience with the Harmony remote and the IR543. There are a number of members that have the Harmony (and love it).
Personally, I prefer to use a palmpad remote (RF) direct to my CM15a/AHP controller. I like the fact that it's not a line of sight control, and the fact that it has nice large button and letters (visually challenged). This does not work for all people. The CM15a doesn't have fantastic RF range. Depending on the size, construction, and layout of your home you may or may not get reliable RF. Just thought I'd point out yet another option.
In addition to the above, you may also require X10 filters and/or a phase coupler. This will depend entirely on the type and location of devices you have installed in your home. Spend a little time looking at the troubleshooting thread. In particular have a look at the following link:
X10 Issues? Please Read This First!Wow, I can see my typing speed hasn't improved recently - 2 posts while I was creating this.
In closing, start slow (minimal investment), decide for yourself how you would like to proceed (home automation is personal), try not to get too addicted.
Boiler
