Meu amigo é gay.

Because amigo is a masculine noun, so the possessive must match it:

• meu amigo = my male friend
• minha amiga = my female friend

In Portuguese, possessives like meu/minha agree with the noun that follows, not with the speaker.

It means both friend and male friend, depending on context.

• amigo = a male friend / friend (masculine form)
• amiga = a female friend

So Meu amigo é gay clearly refers to a male friend.

The accent is required because é is the 3rd person singular form of the verb ser (to be):

• eu sou = I am
• você/ele/ela é = you/he/she is

The accent also helps distinguish it from e, which means and.

So:

• é = is
• e = and

A natural Brazilian Portuguese pronunciation is approximately:

meh-ooh ah-MEE-go eh gay

A few notes:

• meu sounds roughly like meh-oo, but spoken quickly as one syllable or almost one.
• amigo = ah-MEE-goo
• é = eh
• gay sounds very similar to English gay

The exact pronunciation varies a little by region.

Because ser is used for identity, essential characteristics, and classification, while estar is usually for temporary states or conditions.

Sexual orientation is normally expressed with ser, so:

• Meu amigo é gay. = My friend is gay.

Using estar gay would sound unnatural in normal Portuguese.

Yes. In Brazilian Portuguese, both are possible:

• Meu amigo é gay.
• O meu amigo é gay.

But in Brazil, the version without the article is very common, especially in simple everyday statements.

European Portuguese uses articles before possessives more often.

It is a borrowed word, but it is fully common and natural in Brazilian Portuguese.

So gay is widely used in Portuguese just as in English. In this sentence, it does not change form:

• Ele é gay.
• Ela é gay.

The word usually stays the same regardless of gender.

Yes, it can, although in practice lésbica is often more specific for a woman.

Examples:

• Meu amigo é gay. = My male friend is gay.
• Minha amiga é gay. = My female friend is gay.
• Minha amiga é lésbica. = My female friend is lesbian.

So gay can be used more broadly, but lésbica is often preferred for women when being specific.

Not in this meaning.

• Meu amigo é gay. = My friend is gay.

If you say just Amigo é gay, it sounds incomplete or unnatural in normal conversation.

You need something to identify which friend you mean, such as:

• Meu amigo é gay.
• O amigo dele é gay.
• Um amigo meu é gay. = A friend of mine is gay.

They are similar, but not identical:

• Meu amigo é gay = My friend is gay
  This often sounds like you have a specific friend in mind, or that the listener knows who you mean.

• Um amigo meu é gay = A friend of mine is gay
  This sounds less specific and more like one of my friends.

Both are very common.

Yes, in this sentence it is very similar:

• Meu amigo = my friend
• é = is
• gay = gay

So the structure is:

possessive + noun + verb + adjective/classification

That makes this sentence quite straightforward for English speakers.

Only in a very unusual, joking, or nonstandard way.

Normally, sexual orientation is expressed with ser, not estar. So the standard sentence is:

• Meu amigo é gay.

If someone says está gay, it may sound humorous, sarcastic, or simply incorrect, depending on context.

It is normally neutral.

• Meu amigo is neutral and natural.
• gay is a standard, widely used word in Brazilian Portuguese.

So Meu amigo é gay is usually just a straightforward statement. As always, tone and context matter, but the sentence itself is not inherently offensive.