When my dc were about 2 and 4, I went to a friend's father's funeral. Dh played with our dc outside while I attended the service, and then all three joined us for the wake. This had been agreed beforehand with my dfriend.
My dfriend later said that having my dc there was wonderful. Their presence lightened the mood because it allowed people to step away from thinking sad thoughts and made smiles acceptable. The talk soon moved away from sadness to happy memories of his father.
Another good wake I attended was from the first moment intended as a party. 'John' and his wife had been famous for his parties, and his widow was determined to throw one last bash. Loads of good finger food, loads of good drinks. The cocktail John always served, and wine. No beer. John liked the occasional pint, but would never mix hops and wine, nor allow them to be served together. His widow held court, just as at their parties, and everyone flocked around her. There were tears, and laughter, business deals and reminiscences. It really was John's Last Party.
I don't remember a Condolences Book at either wake, though there's been one at every other wake I've ever attended. Maybe there were, but the memories I have retained were of the interactions between the people and the celebration of the deceased, memories of happiness, of love, of catharsis.
Hope your dad's send-off gives you peace.