Hi friend, I'm an amateur composer who just upgraded to EWQL Platinum. I'm happy, but I totally acknowledge your risks are very warranted. Everything's gone smoothly and the one time I did have a problem (last week) I got a reply in a day after reporting the case to ew through their online case system. I solved in on my own. Most installation errors actually can be handled through online research. I think I actually had one when I first got gold. Worse comes to worse though you can literally rip the samples and folders off the disk and install the version of play that's on the website. The only time you run into problems is if the disk if physically damaged or something. Then the only way you can fix that is if you deal with them, which from what I can tell is one of those things that's up in the air. I have no idea if I can tell if my experience is the norm or completely irregular or in between...
Sample player is a software that plays samples, samples being recordings of instruments that are then mapped to midi keys/notes so that you can "play" the instrument. Kontakt is a very versatile player. Where as Play (EWQL's player) only plays 1st party (EWQL's own expensive sample libraries) Kontakt is built off of 3rd party support. Tons of freebies allover the internet, and libraries of different price ranges so you're only obligated to shell out as much as you want. Bonus fact, EWQL developed symphonic choirs and orchestra for Kontakt, they only fairly recently switched to their own sampler for piracy reasons (like in 09). I have Kontakt too, in fact I started with Komplete (Native Instrument's huge library/software bundle). There are tons of orchestra libraries that have been developed for Kontakt and some aren't bad. I will say the cool thing about east west is that it is consolidated material of the same quality in one place, so that makes it feel "convenient" to buy from them.
\
For the keyboard I've gone from basic midi keyboard (a casio) to Oxygen (I wanna say 61) to M audio (45?) The major functions you need for orchestration are velocity sensitivity (which some midi out keyboards like my casio don't have, they also add midi data from their hardware banks), modulation (a mod wheel), and maybe pitch bend. You don't really need to worry about advance functions (I've not used them yet and I've been doing it for 5 years almost). Any other miidi functions can be added to your work in your DAW.
Feel free to ask me more questions, I know how you must feel and I would love to talk and help.