1. The heroes are professionals.
The interesting thing, taking A Bug's Life as taking its plot from Seven Samurai or the Magnificent Seven is that Flik (Dave Foley) is both the Old Man/Emma Cullen summoner role but he is also the Kambei/Chris/Sam leader role of what would be the titular group if this were called, say, Nine Circus Bugs.
3. The villains are very strong.
The grasshoppers come, of course. Like the bandits in Seven Samurai or the original The Magnificent Seven, or Bogue and his hired guns in the remake. A Bug's Life borrows The Ant and the Grasshopper. Hopper (Kevin Spacey) doesn't kill anyone--this is a family-friendly version of the story--but he does threaten it.
4. The society is ineffective, incapable of defending itself.
The best they can do is gather food all over again and send Flik on what they assume is a suicide mission, if he doesn't just give up right away.
7. The heroes form a group for the job.
Taken out of order, here, of course. The heroes here are already a group. They're circus bugs.
6. The heroes all have special abilities and a special status.
As far as special abilities, Slim (David Hyde Pierce) is a prop. Dim (Brad Garrett) can fly. Heimlich (Joe Ranft) is the eater. Francis (Denis Leary) is the hotheaded one. Manny (Jonathan Harris) is the magician. Gypsy (Madeline) is the token female. Tuck and Roll (Michael McShane) fill out their numbers and are acrobats.
Now, taking TV Tropes' "Magnificent Seven Samurai" breakdown, let's see what we've got. Flik is obviously the "hero". Dim is the "big guy".
Manny is the "old guy". Being the hotheaded one, Francis could take the position of the "young guy" but he's almost more the "Lancer." (And, the way the kids take to him, he's pretty close to being Bernardo from the original Magnificent Seven. Slim and Heimlich are both the "funny guy". Tuck and Roll are just extra.
Like Christ-Figuring, Seven Samurai-ing is not an exact science.
2. The heroes undertake a job.
Of course, here you also have a big misunderstanding as a plot device. The circus bugs don't realize they've been hired as fighters, and Flik doesn't realize they're circus bugs. But, Francis proclaims that, regarding their "grasshopper friends" "we are going to knock them dead!" And, they are doomed to become the group Flik thinks they are. But, in a way, that is the case with both Magnificent Sevens as well. Otherwise, why take so much of the runtime on getting the band together and traveling, getting to know one another and letting the audience get to know them. A Bug's Life actually gives this part of the story short shrift. While the bugs do have distinct personalities, the film doesn't seem to be so much about "relationships of the heroes among themselves" as much as--at least for Flik, our hero--"the relationship of the hero to society" (Wright, p. 87, reversed of course). Except, it is not that these things are not happening. This is like The Magnificent Seven if we had just spent more screentime with the Old Man or Emma Cullen, and less with Chris or Sam or Vin or Faraday, and there is no place in family friendly fare for Manny to be "shell-shocked" but he is a Major.
5. The job involves the heroes in a fight.
This is, of course, the whole point.
8. The heroes as a group share respect, affection, and loyalty.
Yes, but not as deeply in this film as in the longer, less kid-friendly versions of the story. It helps here that the group (aside from Flik) already know each other. Less runtime need be spent on them getting to know one another.
9. The heroes as a group are independent of society.
Their lies actually reinforce this separation. They must plan in secret and then re-present their plans to the colony. The brief sequence that cuts together Flik explaining the bird plan, then Manny explaining it, then Princess Atta (Julia Louis-Dreyfus) is damn good use of the visual medium.
Before the plot gets to #10, there is TV Tropes' #4: "The people realize that they can defend themselves, and the team undertakes Training the Peaceful Villagers." Of course, given the importance here of misunderstanding, the colony is tricked into thinking the circus bugs can save them and the bird plan will work. The "training" is just the building of the bird.
And, we can't forget TV Tropes' #5: "The team is forced to leave, whether due to the skepticism or wariness of the villagers or threats from the villains." This is skipped in the remake of The Magnificent Seven but is a big part here--P.T. Flea (John Ratzenberger) arrives and the jig is up, as it were. Doesn't matter if the plan made sense before. If they're circus bugs and not warriors, it ain't gonna work. But then #6: "The team decides to return." Because the Blueberries (the little girl ants for which Francis has become den mother) do a little spying and Dot (Hayden Panetierre) goes after them.
10. The heroes fight the villains.
The bird ruse works. Until P.T. ruins it.
Only after the bird attack falls apart does Flik realize (a la TV Tropes' #4 above) that the colony is stronger than the grasshoppers. And, Flik's realization inspires the rest of the colony. Of course, rain, stronger than the ants or the grasshoppers, ruins that and Hopper seizes the opportunity to grab Flik.
11. The heroes defeat the villains.
Hopper is actually killed (by a real bird, or rather several baby birds). While he had threatened to squash the queen, the practical threat was just that the ants would be without food--which, yeah, realistically would mean death for all of them, but that is far more abstract than explicit, individual death.
12. The heroes stay (or die) together.
Them dying is lampshaded in the children's presentation when the gang first arrives on the island. Then subverted because, duh, this is a family-friendly film.
(That's Wright's (1975) "professional plot" for the western film.)