Mark_Johnson may have already addressed your concern. The Larsen font is not a Smufl font. To use it you need to make playing techniques (for example Strike) and then select glyph, instead of text. Once you are in the glyph editor you can choose the larsen font and select the appropriate symbol in the glyph preview. One odd thing is one of the symbols in not in the basic latin set, but hidden away in punctuation marks. If you can’t sort it out, let me know and I think I can post a project with the markings already in it.
Also, these won’t effect audio playback, as they are only notation. You can set them up to do that, but you need a sample library that has the various articulations already in it, accessible through keyswithces or midi cc. Native instruments Irish collection has some of them, although they are not always appropriate as they are always at the same tempo and emphasis. Not really how actual Irish players ornament.