What are your temps?
Usually, N.ampullaria likes it hot and N.sibuyanensis and N.macfarlenii like it cool. N. x ventrata is bombproof, it can take lowland or highland temps.
My N. ampullaria really declined once temps in my terrerium reached into the low 60's at night in the winter.
The other 2 like nights in the low 50's-low 60's.
If your climate is hot and humid with warm nights, the N. amp would do extemely well outside in the summer. It can take temps up to 100+ if kept moist. If you live in an area with cool nights all summer(less than 60 f), the other 2 would do well outside in the summer. If you have no means of cooling your terrerium at night in the winter, freeze a bottle of water and place it next to your highlanders at night in their terrerium.