Rules question: Vehicles becoming creatures without crewing

[UrizenII]

The LGS to which I go to play Commander on Saturdays has a special theme every other week that adds something to the game or changes deck construction rules.  Once a month, the theme is that each player can choose a Vanguard from the original Vanguard sets to play with (some are banned for balance, of course, like Lyna).  This time, I'm building a Depala vehicles deck with Karn as the Vanguard, and I ran into a bit of a conundrum.

The Karn vanguard is effectively an Emblem version of March of the Machines.  He reads, "Each noncreature artifact you control is an artifact creature with power and toughness each equal to its mana value."  The rule for Vehicle cards in question is 301.7b: "If a Vehicle becomes a creature, it immediately has its printed power and toughness. Other effects, including the effect that makes it a creature, may modify these values or set them to different values."

I see two ways this interaction could work.  Take Smuggler's Copter as an example:
1) As it is cast and before it hits the battlefield, it is a noncreature artifact spell.  When it hits the battlefield, as a check of state-based effects, Karn sees it and makes it an artifact creature with power and toughness 2 (equal to CMC).  Now, since it has become a creature, per the first sentence of 301.7b, it now has its printed power and toughness (3/3).
2) Karn's effect supersedes the printed power and toughness of Copter and makes it 2/2, per the second sentence of 301.7b.

I believe the second scenario is the correct one.  Part 2 of the question: if this is true, can a vehicle "regain" its printed power/toughness if it is crewed?  A ruling on March of Machines from 7/15/07 reads, "If a noncreature artifact becomes an artifact creature this way and then another effect animates it, the new effect overrides March of the Machines’s effect. For example, Chimeric Staff is a 4/4 creature while March of the Machines is on the battlefield. If you activate Chimeric Staff’s ability and choose X = 5, Chimeric Staff will be a 5/5 artifact creature for the rest of the turn."  I understand that crewing the vehicle doesn't change its power and toughness values and that the vehicle in question is already a creature, but crewing it would "animate" it, allowing it to become a creature independent of Karn's effect.  Does that cause it to now gain its printed values, or are they still equal to the card's CMC?

Something like Cyberdrive Awakener or Workshop Elders is very clear, as they would set the base power/toughess of the vehicles as they become creatures.  All the other cards don't seem to be quite as clear-cut (Karn, Silver Golem; Karn's Touch; the +1 ability on Karn, the Great Creator; Sydri, Galvanic Genius; Titania's Song; Toymaker; Xenic Poltergeist; and the Karn vanguard).

[UrizenII]

First: I don't know why you didn't ask in Commander Discussion sub-forum.
Second: Are the Vanguards even legal in EDH?
Third: I just don't think that any of the Legendary cards in Modern make good Commanders. Designer of Wizards, I think, said that. They're just meant for Modern. I have Depala, Pilot Exemplar in a Dwarf-Vehicle deck with Kaladesh-Kaldheim mix, but I don't have ambitions to make her into a Commander. Your choice, but the same goes for Syr Gwyn, Hero of Ashvale. They're just meant for Modern in my opinion and obviously designers' opinion. Good luck.
Fourth: To the topic. I believe this Karn Vanguard emblem makes them creatures with power and toughness equal to their mana value as 2 is the correct one. If you really want to play it. I wouldn't. This is the first time I see it. Why do you wanna play it even? You can use Astor, Bearer of Blades as a Commander instead of Depala. But as said: Modern legendary cards rarely make good Commanders. That's how the game is designed.

1) Becuase it's a rules question, not something specific to commander.  However unlikely, this situation can occur in other formats.
2) No, which is why I specifically mentioned that this is a special set of rules particularly for the commander night at an LGS.
3) That's not relevant to the question, but your opinion is noted.
4) As far as the ruling, I did find out that Karn would make the vehicles' power and toughness equal to their CMC, and then if they are crewed (the "animating effect"), they get their printed power and toughness.

Not understanding why someone would want to do something doesn't per se make that thing any more or less valid than what you would want to do.  Is this whole Karn/Depala thing objectively good?  Absolutely not.  It's just an odd interaction that serves as a creative deck building challenge.  Just because something isn't necessarily good doesn't mean it can't be fun or interesting to build around.  This is literally just a one-off thing for a special event that I thought was funny.  How often do you get to crew your vehicles with other vehicles and hit people with a Sol Ring?

[Aetherium Slinky]

The Vehicle spell on the stack is never a creature. It will always have its printed characteristics unless there's a global effect that specifically modifies cards that aren't in play.

You are a little incorrect: SBAs don't make a card anything. Continuous effects apply all the time, even before SBAs are checked so that SBAs can see the effects. Let's build Smuggler's Copter from scratch. We come to layers.

613.1a Layer 1: Rules and effects that modify copiable values are applied.
613.1b Layer 2: Control-changing effects are applied.
613.1c Layer 3: Text-changing effects are applied. See rule 612, “Text-Changing Effects.”
613.1d Layer 4: Type-changing effects are applied. These include effects that change an object’s card type, subtype, and/or supertype.
613.1e Layer 5: Color-changing effects are applied.
613.1f Layer 6: Ability-adding effects, keyword counters, ability-removing effects, and effects that say an object can’t have an ability are applied.
613.1g Layer 7: Power- and/or toughness-changing effects are applied.

We start with ("Layer 0" in a way) the face of the card. It's a noncreature artifact with the printed qualities.
Layer 1 (not relevant) looks for effects that say "copy", basically. All clones apply their effects here.
Layer 2 (not relevant) looks for the controller of the object.
Layer 3 (not relevant) looks for stuff that changes the text box somehow. I believe Whim of Volrath does this, for example.
Layer 4 looks for the change from artifact to artifact creature. At this point the Copter inherits its printed values of power and toughness.
Layer 5 (not relevant) looks for effects like Cerulean Wisps that change colours of the object.
Layer 6 (not relevant) looks for effects that add/remove/modify abilities. Hall of the Bandit Lord would add haste, for example.
Layer 7 looks for stuff such as the Karn Vanguard that modifies the P/T.

If something with a later time stamp would modify Copter's P/T in layer 7 the object will get that. The only way for the Copter to "regain" its P/T is to remove the continuous effect from the Karn Vanguard (which is impossible because there's nothing that could ever interact with it) because the Crew ability only changes type, doesn't set the power and toughness to anything.

All in all the Copter will cast as a noncreature spell and enter the battlefield as a creature with P/T set to its mana value.

[UrizenII]

The Vehicle spell on the stack is never a creature. It will always have its printed characteristics unless there's a global effect that specifically modifies cards that aren't in play.

That I am aware of.

If something with a later time stamp would modify Copter's P/T in layer 7 the object will get that. The only way for the Copter to "regain" its P/T is to remove the continuous effect from the Karn Vanguard (which is impossible because there's nothing that could ever interact with it) because the Crew ability only changes type, doesn't set the power and toughness to anything.

That's why I referenced and was confused about that ruling on March of the Machines that used Chimeric Staff as an example and was questioning how it interacts with rule 301.7b.  What I'm understanding now is that, even though Crew is an animating effect, Crew does not inherently change the P/T since the vehicle was already a creature because of Karn (per the second clause of 301.7b).  Only if the ability on the artifact itself set the P/T like with Chimeric Staff would it change.

Thank you very much for the clarification.