since splenda is made from sugar, if you arent allergic to sugar, id think you wouldnt be allergic to splenda, but still be careful and dont over do it the first time you try it just in case you are allergic

about the redi whip, if you figure out youre not allergic to splenda, just make your own home made whipped cream. redi whip (at least cool whip did) might have hydrogenated oil which is a carcinogen so youd want to stay away from it. i dont know if that small amount of real sugar will do anything though, my first week on atkins i ate cool whip and i still lost weight..