What did Shakespeare mean by "gild refined gold" [closed]

Yes, it's in a parallel with the rest of the examples. You don't gild something that's already gold, you don't paint something that's already brightly-colored, and you don't put perfume on something that already smells sweet. Look at the surrounding context: "To be possess'd with double pomp [...] is wasteful and ridiculous excess." The idea is that it's futile and wasteful to try to improve on what's already naturally great.

Since you ask about the literal meaning, yes he means gold plating gold with gold.

gild verb cover thinly with gold.

I don't see another meaning. He is simply generalizing an idea with more examples.

Painting a lily is similarly redundant. A mashup of these examples is what gives us the idiom: gild the lily