That sounds about right, Jim. Or at least as good a guess as we're likely to get at this point. I'm also thinking that, if Kelly worked on the 34 and 35, he also did some work on the 37.
More generally, issues 34-37 of Adventures are a creative mess. One thing I will mention about Kelly's involvement: There's no way on Earth he wrote any of those issues. The storytelling in these are a complete mess, and I even think it's possible parts of the story in 35-37 were originally meant for something else. Going from an underwater story back to the surface to fight the Wizard, then dispatching him so quickly they have time to build a house before they go back underwater? The only way I can make any sense out of this is there was a sudden need for pages and they took pages from elsewhere- possibly a 3-part, 12-page serial for Peter Wheat News- and shoved it in to get the 35 and 36 done in time. This might also explain why Kelly looks completely absent from the 36 but, at least to me, looks to have some slight involvement in the 37. (Or at least as much in the 37 as the 35; his involvement in both is minimal if it's there at all.)
I find these issues fascinating, hinting as confusion behind the scenes as Kelly left the title and headed off with Pogo to the newspapers. I just don't find them good.