I would also argue that "whores and scoundrels" is more inclusive. You can be either one regardless of your parts or gender identity.

Strumpets and Scoundrels sounds more high class and has better alliteration

My husband has served as an MC for a few fetish or counter-cultural events, and he likes to open with "Welcome, theydies and gentlethem!

Given the origin of the phrase was extremely classist in Britain. Probably peasants and surfs would be the opposite. Any form of commoner would not be a lady or a gentleman. So reminding people of that.

Though I'm sure the British would do it and I thoroughly British way, introducing Mr Bob and his wife Julia, and now introducing the gentleman lord von butterscotch and his lady affelia.

In the context you would know they were commoners cuz they didn't get the title lady or gentleman

One of my favorite insults is to exclude someone from these classes by simply saying their name afterwards:

"Good morning gentlemen, Steve."

Trollops and scallywags

Bitches & Bastards?

I can only hear Geoffrey Rush's captain Barbossa..."Whores and Scoundrels... "

"Bitches and assholes, thank you for coming to tonight's presentation..."

How about hamsters and elderberries.

Scoundrels just doesn't have the same sting to it as whore does

Personally I think it's more offensive to call someone a booger eater

Wouldn't the opposite technically be "Gentlemen and Ladies"?

Ladisn't and gentlemen't. Or standies and harshmen.