I decided to try WLMessenger 9 Beta. From what I can understand, you can
choose how do online contacts appear ("Nickname" or "Name and Surname").
However, the offline contacts appear as Surname Name when the option display
"Name and Surname" is enabled and with the nickname or (if they have never
been online since you installed WLM9b) with e-mail address when the
"nickname" option is enabled.

Two questions:
1- How do I change name format form Surname Name to Name Surname, e.g., it
appears as "Smith Adam" and I want it to be "Adam Smith".
2- Is there any way so that online contacts show as nickname and offline
contacts show as name and surname? This is because, at least in the
beginning, it is a little difficult to search for someone by their e-mail
address...

Hope I've made myself clear. If not, feel free to ask for details.
I apologize for any possible mistakes in the options cited, as I am using
the Portuguese version and may not have accurately guessed the English
equivalents.