What I love about this Picture is that it isn't about the colors or who fits in which class.



Rather the creator took the personalities of the main 4 and inserted them into the best choices



Ruby>Archer Emiya She fits the memo her younger self easily fits the Shirou Emiya ideals she wants to save people and be a hero and she would save the most rather than the few I can see this dragging her down into becoming exactly like Archer and turning into a Counter-Guardian



Weiss>Saber The Weight of people on your shoulders is a curse and one both bore until the very end while personally, I could totally see Jaune fitting the saber motif (Saber Prototype even?) This suits perfectly for Weiss's personality she can be cold and calculating and isn't the best with people the same can be said about Saber.



Blake> Sabbah Perfect fit not much else I can say here should I even need to say it?



Yang>Ishkandar Gilgamesh does not fit Yang at all or her personality she is not egotistical nor does she believe herself to be higher and above all or the creator of law she is far too easy going and marry for that so Brokandar fits Yang like a glove she is outgoing, yelling and not afraid to state what she believes Yang fits the King of Conquerors quite well.



As for JNPR I can't say who they would be but I can give an idea



Jaune>Ruler I won't say why people who know what the Ruler class is and know who's in it know why Jaune is here.



Pyrrha>Lancer E-rank Luck and always death.



Nora>Beserker Her Mad Enhancement is most likely D or E rank but that doesn't mean she won't brutally beat the crap out of you like a Beserker.



Ren>Assassin Nothing to be said Assassin fits Ren to much.