I think pine is about the same softness as basswood. I know they're both recommended as being very soft and easy to carve.
The following may or may not be any help whatsoever
(Disclaimer: all of my recent woodwork experience has been in making knife handles, so no fancy carving at all, just shaping from a rectangular blank)
If the wood is splitting, I would be tempted to very, very roughly rough out the shape with the dremel, refine it with a sharp knife (preferably with what's called a scandi grind
if you aren't aware of what I mean, and apols if you are
) then finish off the shaping and finish with sandpaper from coarse to very fine (although I know at least one wood carver who really doesn't like sandpaper - but then he's been doing it long enough he can get a really smooth finish just using a knife).
Oh, and before you do any more, have a look over the wood for any obvious cracks and if there are any fill them with CA glue, let set, sand back, fill, and repeat until the crack is full. It can also be used as a final protective coating (some people like it, some don't) - but CA glue will darken the wood!