Раз мы уже всё уладили, давай вечером спокойно поужинаем дома.

No. In this sentence, раз is a conjunction meaning since, as, or if that’s the case.

So:

• Раз мы уже всё уладили... = Since we’ve already settled everything...
• It introduces the reason for the suggestion in the second part of the sentence.

This is different from раз meaning time/instance, as in:

• Один раз = one time / once
• Много раз = many times

Here, it has a conversational, slightly natural spoken feel: Well, since we’ve already sorted everything out...

Because Раз мы уже всё уладили is a subordinate clause, and it is followed by the main clause:

• Раз мы уже всё уладили,
• давай вечером спокойно поужинаем дома.

In English, this works like:

• Since we’ve already settled everything, let’s have a quiet dinner at home tonight.

Russian usually separates this kind of introductory clause with a comma.

Because всё means everything, while все means everyone or all (people/things in plural).

Here the idea is:

• мы уже всё уладили = we’ve already settled everything

Compare:

• всё = everything
• все = everyone / all

Examples:

• Я всё понял. = I understood everything.
• Все пришли. = Everyone came.

So всё is correct because the speaker means all matters / everything that needed to be handled.

Уладили comes from уладить, which means:

• to settle
• to sort out
• to resolve
• to smooth over

So мы уже всё уладили suggests that some issue, task, or problem has been taken care of.

It often implies that things were potentially complicated, but now they are resolved.

Examples:

• Мы уладили конфликт. = We settled the conflict.
• Он быстро уладил все формальности. = He quickly took care of all the formalities.

Because the action is presented as already completed:

• мы уже всё уладили = we already settled everything / have already settled everything

The word уже reinforces this idea of completion: already.

So the logic of the sentence is:

1. We have already finished dealing with everything.
2. Therefore, let’s relax and have dinner at home.

This is a very common conversational way to make a suggestion in Russian.

Pattern:

• давай + 1st person plural verb

So:

• давай поужинаем = let’s have dinner

Literally, давай comes from давать (to give), but in this structure it does not mean give. It functions more like:

• come on
• let’s

Other examples:

• Давай пойдём. = Let’s go.
• Давай поговорим. = Let’s talk.
• Давай останемся дома. = Let’s stay home.

This is informal and natural. If you were speaking more formally or to more than one person respectfully, you might use давайте instead.

Поужинаем is the perfective future of поужинать (to have dinner). In this context, it fits a suggestion for a single complete action:

• давай ... поужинаем = let’s have dinner

Why not the others?

• ужинаем = present tense / sometimes a scheduled or narrative sense, but not the normal choice here
• будем ужинать = future imperfective, which sounds more like we will be having dinner or focuses more on the process

With invitations and suggestions, Russian very often uses the perfective future, because the speaker means a complete event:

• Давай посмотрим фильм. = Let’s watch a movie.
• Давай выпьем чаю. = Let’s have some tea.

So поужинаем sounds the most natural here.

This is an aspect question.

• ужинать = imperfective
• поужинать = perfective

Very roughly:

• ужинать focuses on the activity/process: to be having dinner / to dine
• поужинать focuses on the dinner as a completed event: to have dinner

Examples:

• Мы обычно ужинаем в семь. = We usually have dinner at seven.
  (habit, repeated action)

• Давай поужинаем в семь. = Let’s have dinner at seven.
  (one complete event)

In your sentence, the speaker is proposing one specific dinner that evening, so perfective поужинаем is the natural choice.

Вечером means in the evening / this evening / tonight depending on context.

It is the instrumental form of вечер, but in Russian many time expressions use forms that function adverbially.

Common examples:

• утром = in the morning
• днём = during the day / in the afternoon
• вечером = in the evening
• ночью = at night

So:

• давай вечером поужинаем = let’s have dinner this evening / tonight

You do not need a preposition here.

Спокойно literally means calmly, peacefully, without stress, or in a relaxed way.

In this sentence, it adds the idea that now that everything has been settled, the speakers can eat in peace:

• давай вечером спокойно поужинаем дома
  = let’s have a nice calm dinner at home tonight = let’s have dinner at home in peace tonight

It does not necessarily mean they will sit in silence. It suggests:

• no rush
• no stress
• no drama
• no more issues to handle

So it carries an emotional nuance, not just a literal manner.

Дома means at home, and it is the normal word to use when talking about being at home as a location in everyday speech.

So:

• поужинаем дома = have dinner at home

В доме literally means in the house/building, and it focuses more on the physical building itself.

Compare:

• Я дома. = I’m at home.
• Я в доме. = I’m in the house.

In many contexts, в доме sounds more physical or contrastive, while дома sounds natural and idiomatic for at home.

Yes, Russian word order is flexible, but changing it can shift emphasis.

The original:

• Раз мы уже всё уладили, давай вечером спокойно поужинаем дома.

This sounds natural and balanced.

Possible variations:

• Раз мы уже всё уладили, давай спокойно поужинаем дома вечером.
• Давай, раз мы уже всё уладили, спокойно поужинаем дома вечером.
• Давай вечером дома спокойно поужинаем.

These are all understandable, but the original order is smooth and idiomatic.

The sentence-final дома works well because it gives a nice landing point: the plan is to eat at home, as opposed to somewhere else.

Yes. Давай is informal and is used:

• with friends
• with family
• with people you are on familiar terms with

If you want to be more polite or formal, use давайте:

• Давайте вечером спокойно поужинаем дома.

That can mean either:

• speaking politely to one person, or
• speaking to a group

So in your sentence, давай suggests a casual, friendly tone.

Yes. Depending on the nuance, you could use:

• поскольку = since / because
• так как = since / because
• если уж or раз уж = since / seeing as

Examples:

• Поскольку мы уже всё уладили, давай вечером спокойно поужинаем дома.
• Так как мы уже всё уладили, давай вечером спокойно поужинаем дома.
• Раз уж мы уже всё уладили, давай вечером спокойно поужинаем дома.

But there are slight differences:

• раз sounds conversational and natural
• поскольку sounds more formal/bookish
• так как is neutral
• раз уж adds a shade of since that’s the case now

In this sentence, plain раз fits very well.