Add 'Message Me' button
All functions and features of wpForo PM addon are already described on product page and in docs. There is no option to add Message button on other plugin profile pages. What do you mean saying "main profile"? What plugin you use for this profile page?
I am using a theme that is front end submission/sharing content site so everyone has their own profile. So, when I'm using your forum plugin, the my users now have 2 profiles...one for the forum and one from the original theme (I wish I could combine the two). If you look at someone's profile from the forum, there is a button that says "message me". I was hoping I could put that button the main profile as well if I can't combine the two.