I'm interested in why there is only one non-acorn attraction that you can claim a prize from. Was this unintentional or was there a reason?

The cards were designed a ways before the decision to make the ones that could be Eternal legal, Eternal legal, so we just converted what we could. The main criteria at determining Eternal legality was “can it work in the rules?”. The one wrinkle was the Teddy Bear token that was a prize for some Attractions was pink and the rules don’t handle pink as a color. We’d already made the token and were using Water Gun Balloon Game as a promo and it also used the same pink Teddy Bear token which kept us from changing its color.

Is the Kudo, King Among Bears ability in white's share of the pie? I thought P/T setting was now Blue on the last Mechanical Color Pie update, making Reprobation and Harmonious Archon a bend/break

Green can also do it.

why are mice, squirrels and rats regularly able to kill grizzly bears in one on one combat? I demand justice for apex predators please confirm that you will see to it that future Bears have a size appropriate for their place in the food chain.

Blame the fate of Bears on Alpha and inertia. Grizzly Bears (plural) was a 2/2 originally, and became the core nickname for 2/2’s. A Bear should probably be a base 4/4, but inertia is a powerful force.

Will there be an explanation about how Phyrexians can now hold a spark?

This isn’t my area of expertise, so I’m going to do my best to explain it, but I might get a few small details wrong. Bear me with me.Phyrexians can’t hold a spark. It has to do with the fact that they’re soulless and you need a soul to hold a spark. It’s the same reason some other creature types can’t become a planeswalker (well, without some extenuating circumstance like with Karn). Pre-mending planeswalkers were immune to Phyrexianization based on their ability to have total control over their form. This is not true with post-mending planeswalkers. The Phyrexians are aware of the Multiverse. Prior to the Mending, they used portals to travel between planes, but the Mending shut down the portals (with only once exception that I know of - The Planar Bridge, but even that can’t transport living tissue). Because Phyrexianizing someone removes their soul, it would take away a planeswalkers ability to planeswalk, which is what definitionally makes one a planeswalker. Thus, Phyrexianizing a planeswalker wasn’t a solution to the Phyrexians’ problem. Jin-Gitaxias is on Kamigawa studying spirits made manifest believing that it might hold valuable information for the Phyrexians. It turns out it did and Jin-Gitaxias learned how to compleat a planeswalker without removing their soul/spark. That’s what’s going on. Read the Kamigawa: Neon Dynasty stories for more info.

Strixhaven seems very wordy. (The MDFCs in particular.) Was this a concern in set design?

Word count is a metric we’re always watching. Note that it’s a means to measure complexity, but is not unto itself a cause of complexity. Sometimes twenty words is clearer and easier to understand than ten. The MDFCs are rare and mythic rare, so they can bear the brunt of more words than lower rarity cards that show up at a much higher rate.

If Stet deletes the first seven letters of both Grizzly Bears and Striped Bears, will a Maelstrom Pulse destroy both Bears?

Yes.

I never noticed until just now, but on the Alpha through 4th Edition printings of Grizzly Bears, Dominaria is spelled "Dominia" in the flavor text. Was this the original name idea for the plane, or was it a simple typo that wasn't fixed until 5th Edition?

Dominia was the name of the multiverse originally but people confused Dominaria and Dominia so we just started calling it the multiverse.

It's my birthday today, and my brother's first child is due to be born any day now. Since my brother likes bears, do you have any trivia on a bear-related card?

Bearscape from Odyssey was almost called Bear Supply. I changed it (I was in charge of the names for Odyssey) because not enough people I polled knew who Air Supply was. (It’s a band from the 80’s.)Happy Birthday!

Hypothetical Un-situation: I have "yet another aether vortex" and future sight. Can I cast the grizzly bears from on top of my library, even though it is also technically on the battlefield? If so, how does the game recognize this?

Yes, you can cast it. It will change it from on the battlefield and on top of your library to just on the battlefield which means you won’t draw it and a design different card is now on top and potentially also on the battlefield.

Un-Rules question: I have Yet Another Aether Vortex on the battlefield, along with a Grizzly Bears. I attack with the Bears, and my opponent uses Azorius Charm to put it on to of my library. Is it still attacking them?

Yes. It is immune to “put on top of deck” effects as it is already there.