They're probably just throwing fans a bone and giving small and irrelevant characters a little cameo in the movie.
Honestly, that's actually making me feel more annoyed than nostalgic, since that's not really making cameos, but rather reusing designs of characters I know… For new characters.
Fans: "Hey, it's doctor Croid!"
Filmmakers: "No, that's a completely different Tharpod."
Fans: "Hey, it's Cronk!"
Filmmakers: "No, it's just a Galactic Rangers warbot."
I mean, they could've remade the ORIGINAL Galactic Rangers warbots! Now that's what I'd call throwing fans a bone. I have a similar issue with Juanita - she doesn't seem to be acting as that mean-spirited presenter from Vox News… So why is that Juanita, why not Darla, or even a new character? It's not experience breaking, but to me it's still more annoying than nostalgic.