1,2: I realy like the idea of implementing special prestige mounts. I also like the particle effect.
3: As a pve player I prefer to have some rarity to forms, but I can also understand pvp players would also love a way to get forms you can use for pvp without spending an insane amount of money. So my suggestion would be, that shiny pokemon should be able to change into a mecha form with a recolor. With that pvp players can still use the normal mecha form and collectors have something new to collect. I think it could be an interesting concept. But even if they dont get added I like the idea of improving the pve shop. In most cases i spend my pve coins for rr tickets, but with new prestige mounts and the mecha forms it might be worth saving them.