there is an (actual, this time) error i noticed in your SGRUB diagram compared to that single shot of the actual session map: LORAF and LOMAT need switching around (LORAF should be between LOCAS+LOBAF, LOMAT should be between LOBAF+LODAG). as a side note, why do you think the SGRUB planet order was reversed from the mobius diagram order and SBURB planet order of (clockwise) client planet-server planet to (accounting for alternating teams) server planet-client planet?
Oh, Kanaya and Vriska. Goddammit, I got their symbols mixed up. Thanks for spotting that! I’ve fixed the post accordingly and credited you.
As for the other, I don’t presently have an idea, but you did inspire me to dig into the “order” of the sessions. This required making more maps! :D


(Fun fact: If you keep these maps open and go through A5A1 again, pay attention to how the order the trolls are introduced into the story both parallels and plays with the planet orders! There’s a lot of what feels like metatextual characterisation just in the abstract details.)
BONUS:

That C one’s a bit of a mess, but basically we can deduce that Caliborn’s order of the planets is clockwise, much like the B sessions. You can even see his next planets in the backgrounds of some of his intermissions, and they corroborate even further with this order.
What’s odd is that this means session A is pretty damn unique for being a counter-clockwise session (doubly so, even, because of the teams! and yes I went and double-checked, B2 is clockwise too)! I don’t see why this would be an accident. My preferred interpretation at the moment is that it’s broad characterisation of the entire universe in some way. Clockwork is an important motif in Homestuck’s cosmos, so it’d make sense to see its intricacies pop up in the less-prevalent mechanics as well.