In my opinion, the 3 fonts you mention should be included in the list, but you should also give users the choice of accessing other fonts if they so decide, but you should add a popup warning them that if they choose other fonts, these fonts may cause display problems on other machines with different OSes, what do you think?
Edit: I think it's feasible, if anyone's interested in coding it, why not?
on the font widget list of recommended default fonts add a checkbox with a popup /!\ to warn the user, then we check it on display the complete list of all the fonts installed on the machine.
When it comes to typing in unicode, yes, it's a workaround solution but only for us geeks, not for all our users.....
RE EDIT: We're not Apple or Gnome !!!! .... should not prohibit and block but still leave the choice to those who want it!
I love KDE/ plasma for that!!, you can config and custom your desktop like you want!!