It doesn’t really affect anything. He could have simply told Yaddle he wasn’t going out of grief and then, after the TotJ duel, felt bad and decided to show up and watch Qui-Gon’s burning, albeit probably from afar like in Snooker’s mock-up, after all.
Yaddle told him the council was going to the funeral before the duel, but Palpatine was present for both that duel and the funeral. If Palpatine had time to drop the Sidious persona, regroup with his Chancellor entourage and rendezvous with the council and the Naboo for the funeral, there’s nothing stopping Dooku from making it to Naboo in time for Qui-Gon’s cremation as well.