Speedrunner is S-Tier for the Moo necklace alone, let alone scaring the shit of Nikos by doing nothing. Also The Anthill and "No homo" on top of the fucking embarrassing shit you say if you choose Kota to tend the lounge. Incredible stuff.
I'd say Leader is the most lacking in this build. The benefit you mentioned isn't available yet, but it's certainly pointing to being top tier. In that sense, Art is S-Tier for this build. Not only do you get to pick between Wolf and Themba (because who isn't picking the dreamboat referred to as Khenbish?) but you get some insight into the inspiration behind Mino with his unique conversations about books Asterion wants to order.
Math(s) has Asterion at his horniest, which is hilarious to me.
Humanities has some of the most reassuring dialogue with Asterion. Their unique conversations about ethics and how the world has changed is incredibly sweet. For that alone, it's worth it.
It's why I chose Humanities for doing the Ruthless Master route. :)
Tech I care least about because all programmers know how to do is throw penis all over their code. Good ability, though.