When my ex passed last year, I found our local hospice to be a great resource. They offered a special grief counseling program for children who have suffered a loss. It really helped my 12 yo son. It was offered free to anyone who needed it, regardless of whether the loved one had been a hospice patient.
Hugs to you and your kids. Glad to hear it was a lovely and fitting service and that your wife is finally at peace. Thank you for the update.