I would not go with the fly creek for you. You don't have much experience camping and there may be some times when you will need a creative pitch (it is NOT a free-standing tent). I'd look at their half-dome, quarter-dome, or the new Dash. But again - if you want any kind of "mountaineering" to be done, a super light shelter isn't going to cut it.
That's why I suggested those REI tents - they are great for what you want to use them for. Sturdy enough but not overkill, and you can beat them up (unlike the fly creek). If you had more experience I'd say go with the Fly Creek. Since you don't - then go with the REI brand.
I do like the Tarptent Moment, too tho - I bought that tent for my dad and it's great. I would NOT get the notch, as, again, you don't know how to do creative pitching.
The international is a great international stove - but again, you have no experience and I find white gas stoves to be difficult to learn how to use. Get an inverted CANISTER stove. NOT a white gas one. There are plenty of canisters all through central and south america.
Don't worry about waterproof down - don't spend the money. I also wouldn't do a quilt, either, because they are no good for sleeping in hostels (no bottom - need a sheet, etc).
I like the suggestion for a Kelty Cosmic down - and I think you will be fine with a 15 degree. I'm a cold sleeper as well and this, combined with warm clothes, has been enough for me in all but extreme conditions. and again - you have no business camping in extreme conditions right now.
As your trip goes on and you get more and more comfortable camping, then you may change your needs and you can easily obtain what you need in many of the local shops. As I mentioned, patagonia, for example, has so many gear shops you'll be fine.