Is Spy Network still in color for Blue? Or is having access to that type of information more in Black's color pie nowadays?

It’s still in pie for blue.

Are spies a kind of Detective? Traditionally in Magic they'd either be Rgues or Ninjas, but a few creatures in the set with the Detective creature type look like they're doing espionage more than solving crimes.

When Unstable did them, they were creature type Spy.

With Spy Kit in blackboarder and _____ in Unhinged is it a when or if until we see a card that can be used for Grandeur even though it isn't the same card?

The fact that Spy Kit was printed in black border surprises me to this day. When I first saw it, I literally said, why is this Un-card here?

Was Spy Kit considered as an Unfinity reprint?

The only reprints we considered were the shock lands.

For every player lamenting “I don’t like un-cards being black border because it makes it harder for ME to avoid them”… well, this is how silver-border players have felt for nearly 30 years. I’ve had to ask permission to use my favourite cards every time. That’s why when people go “well you can rule 0 it” it’s disingenuous because those players want their version of the game to be the only default. It’s gatekeeping. Why should I have to ask the commander player with a broken land destruction deck full of legacy staples if I can play contraptions or Spy tribal? I paid money for my cards same as anyone else. I shouldn’t have to ask permission to play my cards when no one else has to. Making un-cards default to being legal means mtg’s default is more inclusive. It’s a good thing.

The previous line between black border and silver border was drawn in an odd place. Mutate and meld are fine, but you can’t use Host/Augment is strange.

since spy kit is already a topic of discussion, something I've always wondered: if I have it equipped on a creature, can I activate princess twilight sparkle's ability and have it work? My playgroup got in a debate since some of the names aren't cards, but personally I feel like it should work given the spirit of silver-bordered magic and also friendship

I’ve ruled it works.

Hey Mark! Are we seeing a shift from colour identity being primarily decided by flavour rather than mechanics? An example from Commander legends wsould be the Opposition Agent a black card flavour wise (being a spy for the Dimir guild) but a white/blue card mechanically (re: Aven mindcensor, Thada Adel, Acquisitor etc.). This is just one of many examples but I am curious to know if this is a design shift or just, for lack of a better term, "mistakes"

Color identity defines what is possible. An ability is primary, secondary and tertiary in various colors. Flavor can define which color, of those capable of the effect, might do it on any one card, but flavor won’t justify the use of something not allowed in a color. Also, a small tip for you. If you don’t understand why something is done, ask so you can get an understanding from the person who is more knowledgeable about the topic. It is better to accept that you don’t know why rather than assume it’s a mistake. It can cause the person you’re asking to see the question as an attack rather than an inquiry and thus might encourage them not to answer. In other words, how you ask a question can impede your ability to learn.

Was there any reason we don't have any common MDFCs? I was looking at making one-land spy for pauper using some MDFCs and when I checked, saw there were none I thought I should ask

It’s the kind of mechanic we tend to do at higher rarities.

Does Spy Kit give the names of cards in rules text?

Not on creatures that are legendary or heavily implied legendary (such as the My Little Ponies).

UN rules question: if I use spy eye, and my opponent has no cards in their library, do I lose?

Yes. The rules simply state you lose if you draw from a library with no cards in it.