Curiouser and curiouser. Your last sentence implies that you're seeking advice on a pretty fundamental area of chemistry involving the reactivity series. It's not rocket science and the answer shouldn't be that difficult to see.
On the other hand, endohedral metallofullerenes are a different matter. I suggest you start looking at Gallium doped M@C60 and then cf Lanthanum.
Yes, it is possible to crystallise the said elements from mercury. I'll leave you to work out how.