Any and all methods can be mixed together to work how you want them to. Even completely opposing theories such as ones using Direct Game vs those usin indirect can be mixed together. It's just a manner of how you do it. However, you don't have to mix up different methods. I have taken up mystery method (I also use techniques from style as it is nearly identical to mm) but I have tweaked aspects to fit my personality. For instance, I do not neg the way mystery says to. I'll tease the girl on stuff but I never do full out negs.

Just a final note: from the way you two are talking it sounds like you have/plan to pay for certain materials. If this is the case, don't do it. I and many other top contributors on here have never paid a cent towards any of the material. Everything you might possibly want to learn can be found for free online. You just have to do a little digging.