A vistoria e o orçamento são para amanhã.

Because Portuguese nouns have grammatical gender.

• vistoria is a feminine noun, so it takes a
• orçamento is a masculine noun, so it takes o

This does not mean the things themselves are feminine or masculine in any real-world sense. It is just a grammatical feature you have to learn with each noun.

A good habit is to memorize nouns together with their article:

• a vistoria
• o orçamento

Vistoria usually means an inspection, check, or official examination of something.

In Brazil, it is often used for things like:

• a property inspection
• a car inspection
• an official on-site check
• a technical inspection before approving or delivering something

So it is a little more specific than a very general English word like look or check.

It can mean either, depending on context.

In everyday Brazilian Portuguese, orçamento often means:

• a budget
• a price estimate
• a quote

In a sentence like this one, especially if someone is arranging a visit or service, orçamento very often means a quote/estimate rather than a budget in the personal-finance sense.

Because the subject is plural.

The subject is:

• A vistoria e o orçamento

That means the inspection and the estimate — two things joined by e (and). Since there are two items, Portuguese uses the plural form of ser:

• é = is
• são = are

So:

• A vistoria é para amanhã.
• O orçamento é para amanhã.
• A vistoria e o orçamento são para amanhã.

Portuguese often uses ser to talk about a scheduled date, time, or occasion.

So é/são para amanhã means something like:

• it is scheduled for tomorrow
• it is set for tomorrow
• it is for tomorrow

Using estar here would sound unnatural in standard usage.

This is similar to other schedule-type sentences:

• A reunião é amanhã.
• A prova é para sexta.

So in this sentence, são is the normal choice.

Here, para amanhã means for tomorrow, in the sense of scheduled for tomorrow, meant for tomorrow, or set for tomorrow.

It does not mean physical movement toward tomorrow, of course. It is a time expression.

This structure is very common in Portuguese for appointments, deadlines, and scheduled events:

• A consulta é para amanhã.
• O serviço ficou para amanhã.
• A entrega é para segunda.

Yes, that can be possible, and native speakers may say it.

But there is a small nuance:

• são amanhã = they are tomorrow / they happen tomorrow
• são para amanhã = they are scheduled/set for tomorrow

So para makes the scheduling idea a little clearer.

In many real situations, both versions would be understood, but para amanhã is very natural when talking about appointments, services, estimates, inspections, and deadlines.

Yes, in this sentence you do.

You have:

• a vistoria
• o orçamento

Since the nouns have different genders, each one needs its own article. You cannot use just one article for both here.

So this is correct:

• A vistoria e o orçamento são para amanhã.

If you removed one article, it would sound incomplete or wrong in standard Portuguese.

It is related, but you should not translate it too mechanically.

In this sentence, para is being used in a very common Portuguese way to indicate:

• a planned date
• a target date
• a scheduled time

So although for tomorrow is a good English translation, the important thing to learn is the Portuguese pattern:

• é para amanhã
• é para segunda
• é para semana que vem

That pattern is extremely useful in everyday Brazilian Portuguese.

These two words are tricky because of nasal vowels, which English does not really have in the same way.

• são has a nasal sound, roughly like sowng without a full ng
• amanhã ends with a nasal ã

A rough learner-friendly guide:

• são ≈ sow with the vowel coming through the nose
• amanhã ≈ ah-ma-NYÃ with a nasal last syllable

A few tips:

• The nh in amanhã sounds like the ny in canyon
• The final ã should be nasal, not a plain a
• The m and n in these words often help nasalize the vowel rather than being strongly pronounced themselves

If you want to sound more natural, the most important thing is to notice that são and the last syllable of amanhã are nasal, not fully oral vowels.