"What is and isn't appropriate when playing characters?"
Woof. Big question and one I get relatively frequently. I don't have all the answers. I think about it a lot. I talk about it a lot. I still don't know. I mean, ultimately, it's not up to me. The only person I can decide this for is myself.
But also, I need *some* kind of framework to talk about this because I teach it! It feels irresponsible to say, "Anything goes!" Because I know that's not true either.
So I've come up with three points to share about this. Again, it's not my final answer; it's not meant to be an exhaustive answer. But it is AN answer to the question.
1) Playing any character that is not yourself is fine. One should hope so. The alternative is never playing any characters and what a poor state we'd be in as performers.
But there's a HUGE caveat: the identity itself cannot be the punchline. If I have an accent as a character, the accent itself is not enough to be "comedy". There are real people with real accents, and their existence is not a joke. Same goes for any aspect of someone's identity. If someone is gay, old, disabled, whatever, playing the fact that they are different in some way for comedy is hurtful. You are saying that this aspect of a person's identity is inherently funny and we should all laugh.
Playing a character who is doing or saying funny things NOT BECAUSE OF THEIR IDENTITY, but because of the other aspects of their character, is totally ok in my books. It's for sure a fine line and needs to be done with skill, respect, and an informed opinion. I think it's very lazy to play one-dimensional characters entirely off of clichés. As performers, you should aim higher than that. As an audience member, I demand higher than that.
1b) Secondary caveat that is 100% my opinion: If you are doing a real accent, it had better be really good. Do not give us your half-ass attempts. That said, please DO give me all your made-up accents. Those are gold.
2) If you want everyone to feel welcome in your improv communities, you need to be mindful of the characters you portray on stage and how you portray them.
If I watch an all-male troupe, and all their women characters are stupid/mean/etc, played to be *laughed at*, then I imagine that group would have a tough time attracting women to join their community. This seems like common sense to me.
This applies to any other minority. If you want people to feel comfortable both as participating members of your community (and as paying members of your audience!), then you cannot play their identities for laughs. I can assure you that minority communities get enough of that outside of improv.
3) When can I play characters based on aspects that do exist in the real world? The safe answer is: when it feels germane or appropriate. Which is 100% subjective. But playing real traits is not easy to do skillfully, any more than it is to play music with skill. You need play characters with respect, intelligence, and sensitivity. All of that takes time, study, and practice. You cannot take two piano lessons and expect to hold a recital.
On top of that, playing someone from a minority community (groups of people who aren't always, and historically have not been, portrayed positively) runs the risk of falling into old, hurtful ways. Ask yourself: do you know enough about the identity you want to play to avoid hurting people? You cannot ignore the history of portrayals of the communities you wish to portray.
You don't even have to guess or assume how people feel about it. Go forth and learn. There are people writing and talking about hurtful and successful portrayals more than ever. Some you may agree with, others you might not. That's ok, too. But you do have a responsibility to educate yourself in the craft you enjoy and make your own determination.
Velvet Wells has a good line about this: "There is always a back-and-forth dialogue between appreciation and appropriation."
The expression I use for new students who want to play characters from minority communities is (I wish I knew who said it originally) "When you are learning to juggle, do not start with the chainsaws." You absolutely can be anything and anyone in improv, but that doesn't mean you should. Reflect on where your comedy is coming from and what you are asking the audience to laugh at.
Be responsible and take care of your fellow performers, your community, your audience, and yourself.