Hills A/D is a great food for syringe feeding. It is a high calorie food that is easily digestable. I typically have a can on hand as a just in case, however you can get away with a good pate style canned cat food. Last year I started using Wellness chicken pate instead of Hills A/D for a hedgehog. She was losing weight on Hills, we switched to Wellness and she regained her weight.
Bene-bac and Ensure are very different products.
Bene-bac is a probiotic meant to help the digestive system when a hedgehog has green stools. A common problem when they are on antibiotics. I personally won't use bene-bac. Instead I use a high count probiotic sold in health food stores for humans. A sprinkle on their food often will help.
Ensure is meant to be a liquid food replacement. I used to use this a lot, but look at the ingredient list. Its not food in my book, but instead its mostly sugar. I typically don't worry about this anymore.