Felices de la vida

Felices de la vida
 

How can we translate this:

Mis primos son felices de la vida cuando les llevo gominolas.

My cousins are as happy as anything when I bring them some sweets.

As happy as a clam... [at a high tide]

As happy as a clown
As happy as a lark
As happy as Larry
As happy as a rat with a gold tooth

Yes, I guess "anything" goes, right?

OK, I had thought of all these (well, except the rat :thinking:), but the problem is that they all sound wrong to me in the plural. You can't say 'my cousins are as happy a clown' and it sounds even worse with 'my cousins are as happy as clowns'. :thinking:

Oh, I see. Good point. I guess you could say,
"as happy as anyone can be"
"as happy as puppies"
"as happy as they can be with life"
And I guess you could still go with the plural version of "clams", "as happy as clams", right?