Were the Horsemen cards referring to roles?

Yes, I'd say that they were indicative of roles.

Jesse Eisenberg as J. Daniel Atlas (The Lovers), a street Magician

In his intro, we can see that women are crazy about him and one of his marks actually attempts to seduce him. The innuendo between Atlas and Henley suggests that they have slept together as well. He is good with banter and plays the role of the host/MC/compère.

Woody Harrelson as Merritt McKinney (The Hermit), a Mentalist

Hermits have … mental powers.

Isla Fisher as Henley Reeves (The High Priestess), an Escapist

At a guess, she keeps the boys under control which she is seen doing a few times throughout the film.

Dave Franco as Jack Wilder (Death), a street Magician

While watching the movie, my reaction was that he had actually died on stage in his spoon-bending intro, but he later resurrects himself by stealing his mark's wallet. This also happens later in the movie.

TVTropes has some interesting notes:

Tarot knowledge also lets a bit more foreshadowing be known; the first card we see in the film is the 7 of Diamonds. The Suit of Pentacles represents martial wealth; all the Asshole Victims in the film have Greed as at least one of their motivations. The 7 of Pentacles itself represents reaching a new level or a prediction of future success, which in both cases is the prediction of the Four Horsemen.

Dylan being called The Fool. The Fool tarot often represents an innate cleverness hidden by an apparent foolishness, foreshadowing that he isn't as stupid as he seems.

You need five cards for a Tarot reading. The five cards are in order of appearance: King of Spades/Swords, Lovers, Hermit, High Preistess [sic], Death. The hidden card is revealed to be the one hidden in backstory magic trick and is the last one that the Horsemen see so for them the reading is: Lovers, Hermit, High Preistess [sic], Death, King of Spades/Swords.

Tarot Motifs: The Eye first contacts the Horsemen by giving them tarot cards — The Lovers (Daniel), The High Priestess (Henley), The Hermit (Merritt), and Death (Jack). This extends to Dylan, the "fifth Horseman," who Thaddeus repeatedly calls 'The Fool' — particularly right before the big reveal. His actual card is the King of Swords. This represents him being a man with an idea, and not being afraid to hurt his victims.

The Lovers symbolizes harmony between male-female, either in yourself or forming a partnership with someone. It is not necessarily sexual. It means being able to take different skills and work toward one goal; finding your co-conspirators.

The Hermit symbolizes the need to find your inner wisdom and gain insight. It's a sign to take a break and learn more about yourself, going deep inside meditation.

The High Priestess is intuitive and in touch with the mystery of the world. It symbolizes your "inner guide" and the strengths inside of you. That gut instinct you have when you know what you have/can/want to do.

Death symbolizes transformation. It's a sign to eliminate things that just aren't working anymore. It's reassurance that you can break old habits and change.

The writers didn't seem to pay attention to the cards' meanings. They just assigned them based on their names and to be edgy. "Oh, she's a girl. Let's give her High Priestess. Oh, he fakes his death. Let's give him Death." The meanings to the cards don't seem to match up with the characters at all.