More shenanigans with Gideon and layers

This is a wonderful trio of cards because of how they interact with each other:

Gideon Jura and Mirrorweave are cards you should already know if you have read my previous blog posts. Veiled Crocodile is a slightly unusual card in that it's just an enchantment that by itself does nothing. However, it has a triggered ability that triggers when a player has no cards in hand, and that ability (permanently) makes it a 4/4 Crocodile creature. (Because it has no "in addition to its other types" it stops being an enchantment, or whatever other types it might have had besides a Crocodile creature.)

Question: Let's assume that Gideon Jura, whose third ability has been used, and Veiled Crocodile, whose ability has triggered earlier, are on the battlefield, and then someone casts Mirrorweave targeting Gideon. What happens to Veiled Crocodile?

One could hastily think that it becomes an unanimated copy of Gideon Jura, the planeswalker uniqueness rule kicks in, and both go immediately to their owners' graveyards.

However, that's not accurate. What happens is that Veiled Crocodile effectively becomes this:

In other words, it becomes a white 4/4 Crocodile creature named "Gideon Jura" with all of Gideon's abilities. It's not a planeswalker and the planeswalker uniqueness rule does not apply. Why?

As we saw in previous blog posts, copy effects happen on layer 1. In this case Mirrorweave is making the Veiled Crocodile permanent a perfect copy of the Gideon Jura card. However, Veiled Crocodile's triggered ability is still in effect, affecting the permanent (a copying effect does not affect any additional effects that may be applying to the permanent.) The type setting effect applies on layer 4, and the power/toughness effect applies on layer 7b.

Since the type setting effect has no "in addition to its other types", the copied type "Planeswalker - Gideon" is completely replaced with "Creature - Crocodile".

This is a rather interesting situation because now we have a non-planeswalker creature that has planeswalker abilities. Can they be used?

As far as I know, the answer is yes. There's nothing in the rules of the game that would forbid a non-planeswalker permanent from using planeswalker abilities if it somehow gains them, as is the case here. The same rules for using them apply, though (in other words, only one can be used per turn, and at sorcery speed.)

Obviously since the permanent has no loyalty counters at this point, only the +2 and the 0 abilities can be used. (Since using the former puts loyalty counters on the permanent, on a later turn if this situation is repeated, it could then use the -2 ability as well.)

What happens if the +2 ability is used? This is a rather unusual situation because the ability talks about something that's just not possible. It's not possible for any creature to attack this particular permanent because it's not a planeswalker (especially since the copy effect of Mirrorweave stops at the end of turn; but even if it didn't, it would make no difference: This is not a planeswalker permanent.) So in practice what happens is that activating the ability puts two loyalty counters on the permanent, and the ability just does nothing. (Creatures are not able to attack it, so they don't have to.)

(The above situation is actually one of the so-called "Magic Golden Rules." Namely, the one that says: "Any part of an instruction that's impossible to perform is ignored.")

If the 0 ability is used, the permanent becomes a 6/6 Crocodile Human Soldier creature. If you have read my previous blog posts you'll know why it retains the Crocodile subtype.

Another question: What if Mirrorweave had targeted Veiled Crocodile instead of Gideon Jura?

Again one could hastily think that Gideon Jura just becomes an unanimated copy of the Veiled Crocodile enchantment, and that's it. However, once again that's not exactly what happens. Instead, it becomes this (I took the liberty of modernizing the card a bit):

As in the other situation, Mirrorweave's copy effect applies on layer 1, and the type setting effect of Gideon is still in effect on layers 4 (setting the type to Human Soldier creature) and 7b (setting the power/toughness to 6/6.) It also retains the Enchantment type because the type setting effect says "is still a planeswalker" which, as we saw in previous blog posts, is a synonym for "in addition to its other types."

In other words, Gideon becomes a blue 6/6 Human Soldier enchantment creature named "Veiled Crocodile", and which has Veiled Crocodile's triggered ability.

If said ability triggers, a new type setting effect is applied. Since it applies on the same layers as Gideon's third ability, but has a newer timestamp, it overrides Gideon's ability and his type becomes "Creature - Crocodile" and his power/toughness is set to 4/4.