No, futures are not traded on Nadex. You can actually trade them with a Broker using Ninjatrader as the charting and trade execution platform. Everything on Nadex is $1 a tick, so if someone is trading an instrument that ticks at a higher dollar amount, they are using a different platform.
As for being nervous about the monthly fee for Apex, I have been a paying member since December of 2014 and I have been earning more than the monthly fee from trading since March of 2015. This past February, I actually became a full time trader, leaving behind a well paying job and I haven't looked back. I am by no means suggesting it's easy, only trying to illustrate that with hard work, effort and time, it is possible. Ultimately you have to decide for yourself, if this is worth the investment in yourself for the potential that it offers.
As for which system I prefer, honestly it could be any system. I have traded IZSS with great success on NQ, Alchemy on Spreads with Forex pairs, so I don't have a preference. I also trade pure price action because I wanted to learn how to do it. You don't need to learn everything to begin trading though. Focus on one system and one instrument, learn it and grow from there. For the better part of a year, I traded NQ primarily and I made enough profit on my trades to sustain myself. I did put a lot of time and effort (every free moment I had) into learning this and was fortunate enough to have a job where I could trade while I worked. Not everyone has those luxuries and therefor, I don't want to set improper expectations for you on when you could be profitable trading live. It could take a month, it could take a year. I will say this, if you are patient, are able to follow a system, can take control of your psychology and practice sound risk management you will find success. I wish I could offer you a blueprint with defined timelines, but it really is different for everyone. It can be done and that alone should provide hope to you or anyone reading this post.
I'm always available to offer help or even just a supportive word. This community has given me a lot and I enjoy paying forward whatever I can. I wish you the best in whatever your decision.