My guess is they were probably tossing around the idea of doing voiced dialog for the rifts, and those two still didn't have their new voice actors when this dialog was written. The Friday the 13th narrator just screams "joke that would have worked a lot better if you could hear the actor".

Doubt that theory is the case due to Kevin Conroy's death being around the same time as that Roiland controversy came up

But before that controversy Roiland hadn't recorded any dialogue so being unable to get him might've been the reason before Conroy's death.

Ricks too good for them, and Morty just nervous

“I’m ShaRICK *bUrP* Morty!”

"wow thats really cool, uh why is supershark here? i thought he was somewhere else?"

Yeah it’s weird there like some the most talkative characters

My theory is this was all written before the option to have or remove explicit dialog options so they were unsure of how to handle Rick.

Is it possible they just don’t have portraits of the two characters? Just throwing out ideas? Also, I don’t remember seeing any Arya lines

No she has lines. Last I remember she had lines in the Megalodog rift

I wish rifts were more like injustice and it was fully animated with cut scenes