Browsers will collapse white space, line breaks are converted to spaces.
Jerboa does not collapse white space, and instead rendered the display name with the line breaks. But, one possible reason is that, the area for usernames/display names can only display 1 line, so all of the pronouns got cut off.
I don’t think there is. The transgender flag is for anyone that is trans. There are transfemme and transmasc specific flags (though they aren’t in Unicode so they can’t be used like I do the trans flag). Do note that transfemme / -masc does not mean transgender woman and man, they describe how one would like to present and/or express themselves.