With a cast of 11 “name” roles and both lead and supporting characters frequently shuttling in and out of scenes, the plot of a three-hour opera can be a bit confusing at times. But in Mozart’s “The Marriage of Figaro,” it all comes together at the end — and happily for all, as a good comic opera should.

“Figaro” was presented Friday night by the New Orleans Opera Association as the final offering of its 2014-15 season. It will be repeated at 2:30 p.m. Sunday at the Mahalia Jackson Theater.

Composed in the decades that followed the baroque era, some of Mozart’s scores bear traces of the legacy of Bach and Handel. Much of the singing in “Figaro” is done in the recitative style of a Handel oratorio: vocalized dialogue with a light harpsichord accompaniment.

Conductor Robert Lyall did a fine job of keeping the orchestra at a level over which the singing could be distinctly heard. The score itself is exquisite.

As Susanna, Figaro’s bride-to-be, Louisiana-born and -raised Lisette Oropesa was taking on one of the most demanding roles in the soprano repertoire. Being in nearly every scene of a long opera can pose a serious challenge to a singer, but Oropesa rose to it. In her arias as well as in duets and ensemble pieces, Oropesa offered a fine display of vocal versatility, from the lilting coloratura of a young woman in love to the confusion and anger of the object of the lascivious intentions of her overlord, Count Almaviva.

As Figaro, bass-baritone Kostas Smoriginas sang with power and clarity, at his best when venting righteous anger on learning of Almaviva’s designs on Susanna the night before her scheduled marriage to Figaro.

In the role of Almaviva, baritone Keith Phares stylishly mirrored the count’s smug entitlement mentality most of the way, but he changed and softened as the character was thwarted by his underlings, and he was believably contrite in the final scene.

Some of the opera’s most memorable arias are sung by Rosina, the count’s long-suffering wife. Reflecting on her fading beauty and the loss of her husband’s affections, her arias “Porgi, amor, qualche ristoro” (Grant, love, some comfort) and “Dove sono i bei moment” (Where are they, the beautiful moments) grab at the heartstrings in such a way as to bring a tear to the eye and a lump to the throat. Soprano Twyla Robinson delivered them winningly.

In the “trouser role” of the young page boy Cherubino, mezzo-soprano Julie Boulianne was outstanding as the sprightly “lover of all women” with the raging hormones and no idea how to control them.

Bass-baritone Thomas Hammons and mezzo Cindy Sadler made a well-matched pair as Dr. Bartolo and his former housekeeper, Marcellina — who apparently did more than just keep house for him. The scene in which they are revealed to be Figaro’s long-lost parents is one of the funniest in the opera.

Tenor Torrance Blaisdell excelled as the smarmy music instructor Don Basilio, who is unable to keep his nose out of everyone else’s business.

Locals in the cast included tenor Kameron Lopreore, of Lacombe, as the lawyer Don Curzio; New Orleans baritone Kenneth Weber as Antonio the gardener; and Loyola undergraduate soprano Aurora Serafine as Antonio’s daughter Barbarina. All three performed their limited roles nicely.

The production’s sets have been around for a while, but they’re still functional and attractive, especially the garden scene in the final act.

It also was nice to see singers and chorus members in period costume, rather than in more contemporary attire, as in some modern productions. Authenticity in both sets and costumes always lends an appealing touch to any opera production, and that’s certainly the case here.