Does the Exp. Share also spread EVs to other members of the team

The participating Pokemon only get experience once. Everybody else in the party gets half of the total each.

Experience gain is independent of participants and number of Pokemon in your party, so yes, your party gains more experience overall if you have more people in your party at the same time.

All pokemon earn experience independently. So the rest of your party does not affect the amount of experience they earn. This is also independent of the Exp. Share's on-state.

I do not know how EV's through Battle work in Gen 6. So I won't comment on their distribution here.

So five example Pancham Battles:

Battle 1a (4 party members):

• Pokemon A participates.
• Pokemon A earned 80 experience.
• Pokemon B,C and D earn 40 experience each.

Battle 1b (3 Party Members):

• Pokemon A participates.
• Pokemon A earned 80 experience.
• Pokemon B and C earn 40 experience each.

Battle Example 2a (Exp. Share On):

• Pokemon A and B participate.
• Pokemon A and B get 80 experience each.
• Pokemon C and D earn 40 experience each.

Battle Example 2b (Exp. Share Off):

• Pokemon A and B participate.
• Pokemon A and B get 80 experience each.
• Pokemon C and D get 0 experience each.

Battle Example 2c (3 party Member Exp. Share Off):

• Pokemon A participates.
• Pokemon A gets 80 experience each.
• Pokemon B and C get 0 experience each.

Traded Pokemon do get boosted experience even if they do not participate.

While evolving a Sylveon for a trade, I stumbled upon a solution. Once I was ready to level up my Eevee, I noticed that he too was receiving boosted EXP. As it turns out, I had messed around Pokémon-Amie with Greninja and he ended up with 2 hearts of enjoyment. To verify this hypothesis, I played with a spare Gabite, defeating a wild pokémon after each additional heart.

With a single heart, there was no noticeable change to the Gabite: she still earned normal EXP and didn't seem to have the thelepathic abilities Sylveon displayed. Once she earned her second heart, she immediately started earning boosted EXP. She also starting dancing at the beginning of battle as Greninja had.

Earning two hearts of Affection in Pokémon-Amie will boost EXP earned for the beloved pokémon