Halcyon gear is very good quality, but tends to sit at the highest price point. The Infinity setup has a number of "extras" that add to the cost -- the Cinch setup, the backplate pad, and the shoulder strap pads. I know people who like those things, but they aren't necessary, and do add to the cost. As you point out, when you can get a backplate and wing AND reg for the same amount of money, it may be difficult to justify a little extra convenience for that much money.
If you wanted to go Halcyon, I'd suggest going with a simpler, basic system. Otherwise, as you have figured out already, you have a number of other manufacturers to choose among, with quite different prices.
Oh, and Tobin will know if you need a long plate . . . I can't remember, off the top of my head, where he feels the cutoff is for that.
A 30 lb wing will do just fine for Vancouver and the tropics (although at some future time, you might ENJOY getting a small, tropical wing -- they're fun). I've had a 130 and an Argon setup in the water with my 30 lb wing, with no problems.