But McCready and Zayne were not among the mourners, a close friend of Wilson's who attended the University of Arkansas with him and helped organize the gathering tells E! News.
"She might have wanted to deal with it in her own way," says the source of the country singer. "I think she wanted something more private with her family in Heber Springs."
Wilson was found unresponsive at their Heber Springs home on Jan. 13 after authorities responded to a report of a self-inflicted gunshot wound. He was pronounced dead at a nearby hospital shortly after 8 p.m.
"It was really nice we could put something together to remember him," the friend said of the memorial. "We had several people speak about their fun times with Dave...He was the most humbling guy. He was real quiet and very calm. Everyone loved him and he could make anyone laugh."
Some of Wilson's old Sigma Nu fraternity brothers attended, as well as a number of fellow musicians.
Wilson "was an amazing musician and friend," the pal added. "He would do anything for anybody. And for someone who went through some personal hardships, including his mother dying, he was a really positive, upbeat guy."
The half-hour service ended with a recording of Wilson playing "Amazing Grace" on the clarinet.
"He was a horn player in the U-of-A marching band," Wilson's friend recalled. "It was really nice to hear something again that he loved to do...He played ['Amazing Grace'] at his mom's funeral six years ago. It was really nice to hear him [at the memorial] play a song that meant so much to him. If you didn't cry yet, you were definitely crying by then. It was pretty moving."
The friend tells E! News that he and others who were close to Wilson wish they could have some answers to their questions about his passing.
"We have said our goodbyes and now we are all scratching our heads, 'Why would Dave do something like this?'" the friend wondered. "He was a really great guy and dad. It doesn't make sense."
Following his death, McCready released a statement mourning the loss of her "life partner" and "caregiver and guiding hand to our sons, Zander and Zayne." Six-year-old Zander's biological father is singer Billy McKnight; McCready has full custody.