I can tell you this much:
As someone who has spent a considerable amount of time programing my own system for the Jewish holidays, there is no easy answer.
According to the Jewish calendar, the day starts and ends at sundown, not at midnight (as in the Gregorian calendar). This presents a lot of complications when programming X10, as sunset shifts throughout the year.
Fortunately, X10 does have dusk and dawn tables, so we can work with it. My "regular" weekly program (I actually have separate ones for winter and summer, as the times are so vastly different) has timers for Friday evening/night, and timers for Saturday.
The holidays add complication, as I need to think about the day/night combinations correctly. For example, in 2009, Passover begins Wednesday evening, April 8th. I need to think about programming for Wednesday evening/night, Thursday (daytime), Thursday evening/night, and Friday (daytime). This is on top of the programming I may need to adjust for Friday evening/night and Saturday.
I usually end up writing a modified program several times a year, and then switching back to my "normal" program after the holiday is over.
It certainly is a large amount of work, but I've gotten better at doing it faster each time.
Since the Jewish holidays are based on the Jewish calendar, they do not fall out on the same dates (on the Gregorian calendar) or the same days of the week each year. At the very least, you will need to write a new program each year.
As for the religious restrictions, it is true that we cannot turn the lights on or off (hence the whole advantage of X10 and the CM15A).
This becomes an issue if there is a power outage at any time over the sabbath (sunset Friday through sunset Saturday) or on any of the holidays.
For my own setup, I created a series of If-Then-Else SmartMacros, with the conditions set based on day of the week and time of day.
The trigger is a PowerFlash module with the contacts shorted together (with a short section of wire). It is set to send a momentary "on" signal when activated.
When power cuts off (for more than 5 seconds or so - there is a capacitor that needs to discharge), and then back on, it sends the signal, which the CM15A interprets to trigger the macros.
Depending on the day of the week and time of day, the macros turn on all of the appropriate lights and other devices.
I set this up several years ago, when we had a long series of brief power outages all through the summer. Or course, by the time I got the PowerFlash and the macros completed, the power company had fixed the issue.
I have only used it a few times since then, but it has worked flawlessly since.
You could probably use something similar to this in your setup.