To answer your original question, each currency has it's own characteristics. For a beginner, I would suggest focusing on one primary currency for trading. Thoroughly learn it's personality and you will be successful. After learning one currency over a reasonable period of time...months to years...then and only then learn another one.
I personally know many traders who learned the markets this way who now trade between 800-1200 lots of their own margin...not on a mini or a
demo...per month very successfully.
It's like a really long courting/marriage process...at first you only see your date's party manners...then they reveal a little bit more of their secrets....eventually you are so intimate with them you either marry them or run screaming and yelling in the opposite direction. You know all their skeletons in their closet. Either way you thoroughly know what makes them tick and how to push their buttons to get the response you want. You also know when to give them a little space so they can calm down and get back to being more reasonable. You know when to hold on to them tightly in a loving caress, when to give them a quick hug/kiss in passing them in a hello or goodbye, or when to head for the pub for the night to stay away from all the nonsense.
For those nay sayers...a question for you. Would you rather marry or have a very close personal relationship with a complete stranger or have one with someone you know inside and out? You know speaking as a medical professional, if you just want one of those quickies with a complete stranger or an occassional/informal relationship with an aquaintance you can have a lot of fun for the night, but you run the risk of getting a life threatening disease. And for those nay sayers that promote casual relationships...unless you tell your frieinds the truth or at least give them some type of prophylaxis...you are promoting their death.
Trawler orgies may have been the thing to do during the 60's, but now they will certainly cause your death. You are right somewhat in thinking there is a close correlation between the majors since they all are crossed to the USD, but they all do not appreciate/depreciate at the same time. Yep maybe your CHF and/or EUR trades will both go good for you, but the GBP usually has a mind full of gin...no offense to our UK members (you are a part of my clan that left for North America in the 1600's...none the less your are my kin)...and the JPY is sneaking around like a ninga ( no offense again as they are very skillfull warriors) in the night waiting for the opportune moment to pounce on you. In other words, you may make money on the CHF and/or EUR, but the GBP you will be flat on and the JPY who knows?
Enough of the analogy already. Hope this helps. Do yourself a favor and stick to just one currency for a while. Which one...that's up to you...which one suits your trading style best? Which one are you naturally attracted to first? Who caught your eye for yet some unknown reason? Yep they all have a personality, but not all personalities get along.
Good Luck on Your Trades, Enjoy Riding Those Waves, and Remember We Are Our Brothers Keeper
Take Care.