Yes

Because Grandpa and Grandma choose their own last names. Poppop kept his and Nanna’s changed when she got married.

Already answered. 

Jade explains here. 

Here are some unsolved plot strings. We also don’t know the full timeline of the Warhammer of Zillyhoo, who sendificated the last frog, or who put the weapons in the Lotus Flower Time Capsule. Those are just the ones off the top of my head. 

The black forms for the adult trolls is just a stylistic approach, just like the human guardians don’t have all of their face’s depicted. Also, all the troll blood colors have been revealed in-canon. 

If they’re dream selves were still alive then they most likely would retreat into those bodies. 

The details of Mindfang’s death were never revealed in-comic so all we know is that he killed her. In the fan animation After Us by toastyhat Mindfang controls the Summoner to kill her to put her out of her misery when she was injured and dying. That’s one way to explain her death. We just don’t have enough information in-canon. 

In-story it doesn’t stand for anything.

Meta-wise it’s a play on Suburb

Nope, just the same base image