Like you said, he went east. Just get out of calcenon and take the stairs on the far right side of route 4.
Maybe ice punch from a guy in peridot ward?
i can trade you those, but i dont have them as 6iv shinies.
you have 3 options:
1. 5iv shines (x in spatk, atk, spatk)
2. 6iv non-shiny
3. 6iv and shiny but created via sandbox.
difficult question to answer. depends on your team, style and stuff.
maybe getting iron tail from a guy at the circus can help you.
im not so good at strategizing, ill just try a bunch of times which order ist the best
first you create an online account over the pokegear - online play
and then one person has to send a request to the other - who is waiting for one - using his online id.
I dont think there is an alternative.
atleast i couldnt find one here and its designated as an event pokemon in the obtainable list.
if you want, i can trade you one.
https://www.rebornevo.com/pr/obtainable/