On 4/10/2021 at 10:38 AM, Bhimoso said:

You will need to donate 2 Metang after you speak to the NPC Steven with over 100 IV total each. They do not need to have your OT, so you can buy some from other players. They must be caught AFTER you begin the quest. BIG WARNING: When you donate them, they will be permanently gone.

i bring 2 old beldum, lvl up them and Steven still take them

Mega Alakazam
 

For the "Compassion" option there's an option to talk to a Alakazam in Snowpoint City, near the port, it ask for a level 100 with the ability Telepathy.
 

 

On 4/10/2021 at 1:08 PM, Bhimoso said:

Pinsir's Megastone can be obtained through winning in the Bug Catching Contest. Unconfirmed if it's just winning once or three times like Beedrill's and Herracross' Megastones

It's confirmed. It was actually my first mega stone ingame which i won while trying for beedrillite