Outer is literally just Outertale!Frisk, so... and he does travel to other universes, so he is acquainted with the main cast. Not Deltarune, though. Not yet, anyway
Same goes with Eliora, she knows most monsters from Outertale (Outer + Eliora are adopted by the Dreemurrs) and other universes as well.
At the rate I’m going, it’s just good RNG and a good strategy, I could break into the 1:15:00 range, possibly lower if things go right without glitches.