Hun virker stædig, når hun ikke vil ændre planen, selv om alle andre er enige.

Virker means seems, appears, or comes across as. So Hun virker stædig is softer and more observational than Hun er stædig.

• Hun virker stædig = She seems stubborn
• Hun er stædig = She is stubborn

Danish often uses virke when the speaker is judging from behavior rather than stating a fact directly.

Because stædig is a predicate adjective after virker, and the subject is hun, which is singular and not neuter.

In Danish, predicate adjectives usually work like this:

• common gender singular: stædig
• neuter singular: stædigt
• plural: stædige

So here:

• Hun virker stædig
• but Barnet virker stædigt
• and De virker stædige

Because alle andre is understood as plural: all the others or everyone else. When a predicate adjective refers to a plural subject, it usually takes -e.

Compare:

• Hun er enig = She agrees
• De er enige = They agree
• Alle andre er enige = Everyone else agrees / All the others agree

So enige is the correct plural form here.

That is just a normal Danish way to express the idea. Literally, alle andre means all others, but in natural English it is often translated as everyone else.

So:

• alle andre = everyone else / all the others

Because alle andre is plural in form, it also matches the plural adjective enige.

Når is used for something that happens regularly, generally, or whenever that situation occurs.
Hvis is more clearly hypothetical: if.

Here, the sentence describes a general pattern:

• Hun virker stædig, når hun ikke vil ændre planen
  = She seems stubborn whenever she refuses to change the plan

If you used hvis, it would sound more like a possible condition in a specific situation:

• Hun virker stædig, hvis hun ikke vil ændre planen
  = She seems stubborn if she won’t change the plan

That is possible in some contexts, but når fits better for a repeated or typical situation.

Because når hun ikke vil ændre planen is a subordinate clause.

In Danish:

• main clauses usually have the finite verb in second position
• subordinate clauses usually put the subject before the sentence adverbial, and the adverbial before the finite verb

So:

• main clause: Hun vil ikke ændre planen
• subordinate clause: når hun ikke vil ændre planen

This is a very important Danish word-order pattern.

No, here vil means wants to, is willing to, or is prepared to. With ikke, it often implies unwillingness or refusal.

So hun ikke vil ændre planen means:

• she does not want to change the plan
• she is unwilling to change the plan
• she won’t change the plan

It is not mainly a future meaning here.

Because ville is a modal verb, and modal verbs in Danish normally take the bare infinitive without at.

So you say:

• hun vil ændre planen
• not hun vil at ændre planen

This is similar to English:

• she will change
• she can change
• not she will to change

Other Danish modal verbs work the same way, such as kan, skal, må, and bør.

In Danish, the definite article is often attached to the end of the noun.

So:

• plan = a plan
• planen = the plan

This is very normal Danish grammar. The ending -en is the singular definite ending for many common-gender nouns.

You use a separate article like den mainly when there is an adjective:

• planen = the plan
• den nye plan = the new plan

Selv om means although, even though, or even if, depending on context. Here it introduces a contrast:

• selv om alle andre er enige
  = even though everyone else agrees

So the idea is: her behavior seems stubborn despite the fact that everyone else agrees.

It is best to learn selv om as a fixed expression rather than trying to understand it word by word.

It has:

1. a main clause: Hun virker stædig
2. a subordinate clause with når: når hun ikke vil ændre planen
3. another subordinate clause with selv om: selv om alle andre er enige

So the pattern is:

• main statement
• circumstance/time-pattern
• contrast

That kind of layering is very common in Danish.

Because Danish normally uses commas to mark the beginning of subordinate clauses.

Here:

• , når hun ikke vil ændre planen
• , selv om alle andre er enige

Both når and selv om introduce subordinate clauses, so the commas help show the sentence structure clearly.

Yes, stædig usually has a somewhat negative tone, like stubborn in English. It suggests that someone refuses to change their mind or behavior, even when there are good reasons to do so.

It is not the harshest possible word, but it is definitely a criticism in most contexts.