Although I'm constantly going through the series, I don't always watch this series and the episodes that deal with Compo's death. Mainly because I get too emotional! Seeing Bill Owen in the poor condition he was is depressing, and I tend to get distracted by the obvious changes they made to make the episodes work after his death. At any rate, I did watch the series over the last few days and came away thinking that "Elegy" on its own very probably would have been enough as a goodbye to Compo. Its not that I don't like the other two episodes (and I still cry at the end of "Just a Small Funeral"), just that I don't think they add a whole lot to the catharsis the audience needed. "Elegy" covers all the bases by itself - Compo's death, the immediate reaction of the characters, and a chance to say goodbye. Introducing Reggie in "Surprise" and having the actual funeral in the third episode don't seem necessary, IMHO.
Of course then I watched the last four episodes that introduce Tom and continue to think they are largely a mistake. I still wonder how the show survived that since by all accounts it went over very badly with the audience. Neither of the books I have on the show really explain how and why the BBC decided to keep the show going after Bill Owen's death, even though both suggest it was up in the air for a time.