Hi and welcome!
For the soups, there actually isn't any substitute. The soups count as a lite because of the soy protein, and any over the counter things like the "cup a soups" don't have the same calories, protein, fat, etc. and are much, much higher in sodium.
As for the protein thing, I was told not to mix also, so I don't. Other people have been told you can split the protein, just not mix it. So you could have 1/2P eggs for breakfast and then 1/2P steak for lunch. Not sure of the nutritionals behind it, it's just something I've done for so long that I don't even think about it now.
The best advice I can give someone new to the plan is to just "do what you're told". This plan is unlike any other you've ever been on. It doesn't allow "anything in moderation" as many other programs, but the success rate is very high for those that follow it. You eat your own food, and while doing that you are learning how to eat for the rest of your life. So instead of fighting the program, just resign yourself to the fact that some things don't exist for you right now, but they will all be there waiting for you in maintenance.
TURKEY DAY CHALLENGE