I wish I was working with a Genuine HD service manual but I am not. I only have a general Clymer manual for your year & model bike. Do you happen to have a Genuine HD manual.
I am hoping that the code charts I am looking at, are in-fact correct. Aftermarket manuals can have "holes" in them. That's just the way it is.
I can only tell you what I would do if this was my bike and how I see the problem from a remote location. First off, getting a new 24 code (front coil issue) is very strange. It's hard for me to believe you actually now have a coil issue also. But what's in common between the 23 & 24 codes is the power source. Look at the attachment. Do you have this fuse/relay block on your bike?
The very first thing to do: The coil connector has 4 wires. One should be a Yellow w/ Green (terminal "A") which is the power source. With the engine OFF, compare the voltage directly across the battery, to the voltage you read between terminal A and Frame ground.
Place meter probes directly onto the battery lead posts. Compare that reading to what you read at terminal "A" of the coil and the frame. What do you read? Do not unplug the coil connector to read the voltage. Try to back-probe the connector.
After doing that voltage comparison, I would inspect/ clean/ lube/ tighten the following items.
1) The battery terminals. Remove, wire brush and re-tighten. Don't grease up the terminals until AFTER they are installed and tighten.
2) The ECM fuse.
3) The System relay pins and socket
4) The 36 pin ECM connector. (Before inspecting the ECM connector, disconnect the battery)
5) The 40 amp main breaker.
Even if your eye-sight is good, it is always best to use a set of inspection glasses when looking at pins, pin receptacles and crimp connectors. Look for signs of discoloration which indicate heat, electrolysis, pitting, loose fitment, spreading of receptacles, fretting etc. On a 12 year old bike, things you would not normally see can exist