I might be misunderstanding you, but the F-1015 is not in the assembly with the F-1034 bulkhead - it is further forward. I think you mean F-1018 for reference to the keeper rivets. The F-1015 has the gotcha.
Page 26-5 step 6 is telling you to hold off on drilling the aft holes because you don't have them joined up with the F-1034 fuselage bulkhead and the outer skin which is installed in Sect 29. The keepers are not part of that, so you can proceed on 26-6 with drill/dimple - but if you did the whole row you'd have an enlarged hole for the skin to mate with.
Reference 29-15 step 1 for the dimpling instructions. It calls out the F-1034, but I'm not finding the F-1018 specifically.
Forgive my memory. I know I drilled out these "keeper" rivets a couple times. No big deal. These on the end have easy access for a dimpler later on.
I would give a shout out to Mike and Sarah's blog (since you already mentioned Justin's and Ed's). They also have a nice write-up that might provide additional perspective.