Symbolism, Imagery, Allegory
We already know that Bud's name means a flower bud, right? So it's no accident that when Bud finally ends his quest to find a home and a family in Bud, Not Buddy, it's inside the Sweet Pea that it happens. A sweet pea is a flower, and like Bud's mother said, Bud is "A flower-in-waiting. Waiting for just the right warmth and care to open up […] waiting to unfold and be seen by the world" (5.42). When Bud finally cries for the first time in a very long time and feels like he has found his people, the Sweet Pea was the place he could do this in.
But there's more. Because both Bud and the Sweet Pea are words that have something to do with flowers, it's almost as if there's a connection between Bud and the restaurant. And there is: Bud's new family—and the last living member of his first family—all gather in the Sweet Pea restaurant. But the Sweet Pea restaurant isn't complete without Bud, either, so it's almost as if the names Bud and Sweet Pea tells us that Bud and the people at the Sweet Pea are meant to be together in the end.