No worries, mate! You'll have no problems with Atlantic salmon as long as you keep two things in mind:
-Atlantic salmon usually prefer a faster fly than all but the most aggressive summer steelhead. On a floating line, we often bring the angle of the cast up around 80 degrees (where 90 degrees is straight across current), and mend DOWN. The exceedingly vast majority of summer-run fishing for Atlantics is done with a floating line.
-June and early July fish can be very heavy. I'm usually on 12# Maxima if the water is up and there a quite a few big fish around. With the water high and the potential for big salmon, I'm not a fan of click/pawl reels: I've seen too many people cleaned on 'em with early-season fish. A disc drag reel usually helps land the fish more quickly, particularly at the end of the fight where the angler can use the drag to make the fish really work for any line pulled off the reel.
With all due respect, I'm not sure that I agree with D3Smartie's comments: I have fished the very finest private water on the Grand Cascapedia and Miramichi. With loads of fish, no competition from other anglers, and a guide to position the Sharpe's (canoe) the angling WAS very straightforward.
Public water angling for Atlantic salmon--where the fish are almost always fewer and the competition can be rather stiff--rivals any steelheading on the Skagit, Sauk, Stilly, Sky, Clearwater, etc., that I have done for pure difficulty in hooking up. I like both experiences, but lean towards public water fishing as I can generally run around the river a lot more.
The fishing in Quebec can be very reasonable: a fishing pass is usually around U.S. $45.00 (and gives you access to more pools than you can fish in a day), and motels and campgrounds are very inexpensive. I often "dirtbag" it, i.e. sleep in the back of the pickup truck in a friend's driveway. I usually look for fish first, then go buy a pass so I can fish for them; saves time as I know where they are ahead of time.
Good luck in Newfoundland!