What are the implications of positive/negative answers to these questions, and/or what else aside from "because it's there" motivates answering these questions?
Who knows? Answers to these questions might spur discussion on connections between cellular automata and other computational constructions. I think that's Wolfram's angle -- justify the cellular-automata-is-everything tack that he's been on the past 20-30 years.
"If one can show that a system is universal, however, then this does have implications that are closer to our rule 30 problem. In particular, if a system is universal, then there’ll be questions (like the halting problem) about its infinite-time behavior that will be undecidable, and which no guaranteed-finite-time computation can answer."
