Maid of Honor
Adrienne and Elyssa have been friends since homeroom with Mr. Haas in 6th grade. In 9th grade they were in English together and Adrienne was over at Elyssa’s to work on a project. Alfie, Elyssa's beloved first cat, peed on Adrienne's arm. Adrienne and Elyssa were in English together again in 11th grade and, despite the cat pee incident, they were so happy and chatty, their teacher threatened to axe them in the heads, Raskolnikov-style.
Bridesmaid
In middle school, Beth played one of the lead roles in a production of Anne of Green Gables. Elyssa played Beth's mom. It was a career high for both of them.
Bridesmaid
Jim told Elyssa he loved her for the first time in the parking lot of of Quality Inn & Suites in Northampton, MA. It was snowing and Alice had locked them out of their hotel room and then fallen asleep. They love this story and they love Alice (Elyssa most) so much.
Bridesman
Elyssa sat in front of Neill in middle school chorus and it's a miracle they're friends because he was (his words) way too cool for her back then.
Bridesman
Tom is Elyssa's oldest friend; they had playdates together in preschool. He is excited the wedding ends at 10 p.m.
Bridesman
Elyssa is a little bossy. Once, Nick made her a small, cardboard guillotine because it's something a ruthless queen would want. She still has it.
Best Man
Bachman and Jim are Eagles fans. That's not the only reason he is the best man, but it is a reason. Another reason is that because their last names are close alphabetically, they sat next to each other in homeroom from 2000-2006. During that time they conducted various shenanigans that are neither inappropriate nor embarrassing, but without proper context would cease to be funny. You can ask them about it, but chances are their story will be loaded with side information, tangents, and "holy shit, remember when X happened..." so your question may not get answered. Could be worth the risk though.
Groomsman
Henry and Jim have been friends since middle school. One time, from 2007 to 2010 they played Call of Duty 4 together at Dawson's house.
Groomsman
Jason was actually Jim's first marriage. It was a small ceremony in front of Mrs. Beauchene's study hall in middle school. Bachman officiated. The two have since parted amicably.
Groomsman
Dan and Jim became friends in pre-school, but their friendship really hit its stride when Jim needed someone to copy off of in his 3rd grade advanced level math class. After several weeks of smooth sailing, Dan's desk got moved across the room. Jim was subsequently demoted to the regular math class where he continued to struggle.
Groomsman
Trevor and Jim grew up together in Barkhamsted which means they were approximately .000572% of the town's population*. *Numbers based on 2000 United States Census data.
Groomsman
Dawson, Dan, and Jim once went to Burger King. Dan and Dawson each ordered the quad-stacker while Jim ordered a triple-stacker. He will never live that moment down.