Stativ på den ene siden, frihet på den andre.

Because this is a shortened, elliptical phrase, not a full standard sentence with a finite verb.

Norwegian often allows this kind of compressed style in:

• captions
• slogans
• advertising
• headlines
• punchy contrasts

The full idea might be something like:

• Det er stativ på den ene siden og frihet på den andre.
• Et stativ på den ene siden, frihet på den andre.

But the original sounds more concise and stylistic.

The two nouns are being used in a compressed contrast.

For frihet, this is very natural, because abstract nouns are often used without an article when talking about the idea in general:

• frihet = freedom
• kjærlighet = love
• håp = hope

For stativ, dropping the article is more of a stylistic choice. In a full ordinary sentence, you would often expect:

• et stativ

So the lack of articles gives the whole expression a more headline-like, slogan-like feel.

It is a very common Norwegian contrast pattern meaning roughly:

• on the one side ... on the other
• or idiomatically on the one hand ... on the other hand

Literally:

• på = on
• den ene siden = the one side
• den andre = the other

In this sentence, it sets up a contrast between two things:

• stativ
• frihet

Depending on context, it can be:

• literal: physically on one side and the other side
• figurative: one option versus another, one aspect versus another

Because ene here is part of the fixed expression den ene ... den andre.

This is not just the number one in the simple counting sense. It is the special form used when contrasting one of two things:

• den ene = the one
• den andre = the other

By contrast, én is usually the stressed numeral one, often used for emphasis:

• Jeg har én bil, ikke to. = I have one car, not two.

So in your sentence, den ene is the correct form.

This is a very common learner question.

In this kind of pairing, Norwegian normally uses:

• den ene ... den andre

So andre is the expected word here.

A useful rough distinction is:

• annen often means another / a different
• andre often means the other or appears in definite/plural contexts

Examples:

• en annen bok = another book / a different book
• den andre boka = the other book

So in your sentence, where the meaning is the other side, den andre is the natural choice.

Because the hidden noun is side / siden, and side is a common-gender noun in Bokmål.

So:

• den ene siden
• den andre siden

not:

• det ene siden
• det andre siden

Even though stativ itself is a neuter noun (et stativ), that does not matter here. The word den belongs with side, not with stativ.

Because siden is omitted the second time since it is already understood.

Full version:

• på den ene siden, på den andre siden

Shorter version:

• på den ene siden, på den andre

This kind of omission is very natural when the missing word is obvious from the first half. It avoids repetition and makes the phrase sound tighter.

So both are possible, but the version with på den andre is more compact.

Yes, but it sounds stylized rather than like everyday neutral prose.

It feels natural in contexts like:

• a slogan
• a caption
• a marketing line
• a dramatic contrast

In ordinary conversation or plain prose, people might more often say something fuller, such as:

• Et stativ på den ene siden, frihet på den andre siden.
• Du har stativ på den ene siden og frihet på den andre.

So the original is natural, but it has a deliberate compact and rhetorical feel.

Yes.

It can be literal:

• something is physically on one side, and something else is on the other side

It can also be figurative:

• one consideration on one side, another consideration on the other side
• like English on the one hand ... on the other hand

Without more context, the phrase itself allows either reading. The rest of the situation tells you whether the speaker means actual physical sides or a more abstract contrast.

Not if you want the same meaning.

• på den ene siden is a fixed contrast pattern: on the one side / on the one hand
• på en side just means on a side or sometimes in one way
• på én side gives extra emphasis to the number one, but it still does not sound like the standard paired expression

So if you want the contrast one side ... the other side, the normal form is:

• på den ene siden ... på den andre siden