I am an artist of the faithful ressource pack and I decided to embark on the adaptation of unicode fonts, I found myself stopped when I realized that it was impossible to do my job correctly :

1) When I put unicode font at ON, all caracters are replaced by white square :
(Screen with all white square unicode font on) 

2) Unicode files doesn't change anything when I modify them :
(the proof in the picture of the panel and the file unicode_page_2b, the one containing the arrows present on the panel, we can notice that the arrows are not resized as the letter z present on the ascii file. this means that the textures of the unicode pages are not taken into account by the game)

YOU CAN ALSO DOWNLOAD THE RESSOURCE PACK HERE : https://faithful.team/news/2019-06-01-faithful-1-14-3-r1/