I only do UT shinies, so the only one out of those I would be able to do is Scyther, since Gallade would be too much work to EV train and Shaymin is only available in Plat, which I have no intention of getting.
I can do your UT Adamant Scyther, but I make no promises on Metal Coat. I'll try to find one and attach it so you can get a Shiny Scizor through trade.
I like your offers, and as long as they are UT, I have some good incentive to get this done before April 3rd. According to Serebii, Scyther is found at Route 229 at Level 52. I'll get it done ASAP and VM you.
For Gunners, I am still waiting for a Smoochum swarm, I never seem to have gotten it yet. If you still want your Smoochum, just VM/Post so I know to check the Swarm.
NOTICE: Saved in front of Giratina in Turnback Cave and waiting for the right IVs and nature to EV train. If you have any suggestions on the EV spread I should do, VM me.