I did buy some real plants, could I have them AND silk plants? yup but be careful as some plants need high light and if you get the tube ones from petco most are NOT aquatic. Amazon sword, anubias and water sprite come in tubes and those are good ones to have.
Would I have to cycle the tank before I put the plants in? no, plants bythemselves can do some kind of plant cycle but you need to have certain kinds, I think.
Do they need a specific type of substrate? I currently have white(ish) aquarium gravel - no but there are special gravel like substrates that are just for plants. Caribesea's eco complete is one of them. Seachem ( I think) also has one but they are nor necessiary. You can use root tabs which are like round waffers you place into the substrate.
Or you can do a true natural planted tank with soil and sand. I just have sand and use root tabs and liquid fert for my plants
I got most of mine online from plnated aquariums central. Any of the ones in the beginner section would work. You can just do one or two small anubias tied to a rock if you want, since you have all those silk plants.