The HExs are just that - extras which make sure you're getting certain nutriments. If you're sure you are getting all you need from your diet eg eating lots of yogurts or cottage cheese for example so that not having cheese or milk is not leaving you short of calcium, then yes, you can skip them but you can't replace them with different Synned items. I'm sure you can appreciate that it's not exactly healthy to replace wholemeal bread with crisps! (Not that I'm suggesting you would do this, but some people might if it were allowed).
Have another look at the lists. The B choices include, amongst other things, cooked and dried fuits, olives and extra virgin olive oil (which could be used instead of Frylight) as well as cereals, bread and crispbreads.