darkSpyro

In Cloud Patrol you can link your actual figure to the character in the game through either the portal or using the webcode.
I noticed that it is also possible to link? the Rocket Booster and the Magic Item Slot or at least they have a crown+ sign next to them. Does anyone know if they can be unlocked with a magic item figure through the portal?

No, because there is no figure for those items. They can only be bought with gems; note that when you choose those items, the crown sign is actually grayed out on them and can't be tapped, meaning you can't register them with a code or portal because they're not actual figures.