Spine's runtime rendering is separate from its data model. You could animate a Spine skeleton and then use the bones to transform SVG meshes instead of texture regions.
You can animate in Spine at one resolution and use a different resolution at runtime. Not sure what you mean by aliasing. In skeletal animation texels are almost never aligned with screen pixels, so there will always be filtering. It's not normally an issue because everything is moving, since that is the point of animating after all. 🙂