no, you can't get the pressed event, buttons usually trigger the click event on released which is what you usually need. if you need something different you can create a new version of ofxButton, ofxButtonPress? which triggers the event on pressed instead of released or triggers both using a boolean event instead of a void one
no, utf8 is not supported yet for rendering text in OF. there's already a pull request, that won't make it into 0.9, which will add support for utf8. even with that the default font for ofxGui is very limitied and won't have support for utf8. you can change the default font by calling
ofxBaseGui::loadFont("someutf8font.ttf",fontSize);but as i said this won't work until after 0.9
