Getting over Candida is confusing at time for sure, but I think there are some things everyone agrees on.
Diet sodas and processed food in general is shit. Why not? Aspartame. It creates brain fog and head problems. And despite it having no calories, actually makes you fat. And a host of other problems, if you want to look it up, look on http://www.Mercola.com
or this website or anywhere. Do yourself a favor, stop drinking it, you'll feel better in the long run.
I have no idea why they are saying you should eat potatoes, because potatoes are starch and anyone on a "Candida diet" should limit or eliminate starch in their diet.
Spicy foods increase circulation, promotes health. Imo, they had nothing to do with me getting over Candida however.
Homemade soup is great, go for it.
Popcorn is a mild starch. On a strict diet you shouldn't, on a less restricted diet, some is ok. Make sure it's organic kernels (you don't want Genetically-Modified-Organisms corn) and that you don't use a microwave. Microwave is terrible for Candida btw, it messes up your intestinal flora even more. Stupid microwave was sending me to the grave, might not be as dramatic for you, but it still hurts over time.
I don't understand your last part.
Candida... is commonly confused with other problems because everyone's Candida symptoms are different!
The BEST diagnosis for Candida, imo, is to take the drug nilstat or nystatin for 2 weeks. If you get die-off or you feel better, you have Candida. If you feel nothing, you don't have Candida! I find it such a shame to see people trying to cure Candida for years when they don't actually have it in the first place.