I would like to know if you can use  2D line drawings lowpolgon cartoon characters to make 3D models, and if so, how, And can you export to flash?      

I'm not entirely sure what you want to do, but there is an excellent application called Swift3D which can create Illustrator or Flash objects (with animation) from 3DS objects. its also available as a render plugin for 3DSMAX. However, it doesnt use textures, so how it would work with IM, I dont really know.