It is possible to do a 3D blend already using the Lerp Real list function from Martinus Magneson's Utilities
See the thread and example here for Save Frames To Movie with audio: https://vuo.org/node/2343
Here's a ribbon with UV's.
Sorry to say this comp does not make vertices which make for tidy faces.
Try adding a flat colour shader instead of wireframe and you will see the issue.
Adding a facetize does something to rid of the error.
Yes I get the same gaps with mouse input.
Here's a screenshot using Leap Motion input, no gaps: