It can be endless. Also, if you sign articles, you risk having readers calling you directly for more information, with pesky questions, and with requests for guidance on how the article may impact on them. Also, if you put in e-mail addresses, you risk giving the impression that your firm is not the traditional, stolid place your clients expect it to be. Don't use color. That's what other serious documents like wills, deeds, and summonses look like.
Color suggests life, stimulation, variety, fun, and emotion.
It also appeals strongly to younger people who have grown up with TV and expect it. You've got to decide whether you want to be taken seriously as a crusty professional with a traditional image to uphold or whether to condescend in ways that reach people on their levels. Ignore rules of writing and layout that help people read and understand. It'll do your readers good because they need the intellectual challenge, and it will reinforce that professional distance that is so important. Besides, explaining things in plain English is condescending.