I know the Gem V was molded into the F Skewb with extensions. Can we do the same for the other puzzles?
Most of theDayan gems are truncated octahedrons or already truncated in some way. If I understand you question yes you can "untruncate" them. In the case of the dayan gem V it's possible to transform it into a F-skwb because it's a truncated octahedral version of the f-skewb. Same goes for the dayan Gem IV. It's a the truncated octahedral form of a dino skewb.
My grapes are making noises right now. They keep saying drink me, drink me.