Hey Bear, welcome to the forum. You have a lot of great fishing in Portland, so you should have a blast, and you've picked 2 great fly weights, the 5 and 9, to cover you for a huge variety of different types of FF. Feel free to ask questions, there are a lot of helpful folks here that can get you off to a good start.
I don’t have any experience with the G Loomis fly reels, so you might want to ask for opinions on the gear forum under reels. But judging by the specs, the EastFork 7/8 will hold an 8 wt fly line with 150 yds of 30lb backing, which would be about 125 yds of 30lb backing with a 9 weight line. That should be fine for steelhead and kings. (If you were to fish for bonefish on the flats in Fla for example, you might want more backing capacity and could switch to about 185 yds of 20lb test Dacron.)
Other alternatives you might consider for reels are:
Lamson Konic 4 for use with 9 and 10 weight rods capacity is 240 yds of 30lb test Dacron with a weight forward 10 weight fly line, which would be about 270 with a weight forward 9. The reel goes for about 150 bucks. It is a pressure cast aluminum (as opposed to machined) reel, with a very good drag.
Lamson has also recently discontinued a few models of their fully machined reels that you can find at about 30% off list, with some places throwing in a free or discounted fly line:
Lamson Radius 3.5 for 8-9 weight rods, backing capacity 200 yds of 20lb (or about 170 yds of 30lb) with a 9 weight fly line, suggested retail 219 now 153.30
Lamson Velocity 3.5 for 8 and 9 weight rods, backing capacity 200 yds 20lb(or about 170 yds with 30lb) with a 9 weight fly line, suggested retail 289 now 202
As far as knots go, you’d use the same knots for different weight fly lines
Arbor knot- for backing to fly line
Albright knot- for backing to fly line.
Albright or Nail Knot- front of fly line to butt of leader
Double Surgeon or Blood knot tippet to front section of leader
Improved Clinch knot or non slip mono loop knot- fly to tippet
You can find them all here:
Grog's Fishing Knots Index
You can also use a loop to loop connection using two perfection loops between fly line and backing and fly line and leader for quick changes by connecting a short section of backing to the fly line (with an Albright knot), and a short section of 30lb or 40lb mono to the front of the fly line (with a Nail or Albright knot) knot, and making 9” perfection loops in the backing attached to the fly reel and the backing attached to the fly line. (This will allow you to change fly lines quickly if you want to switch from a floating line to a sink tip for example without the need to carry a spare spool) .
For the connection to the fly line and leader. A 2” perfection loop in the 30 or 40lb mono attached to the fly line, and a small perfection loop in the butt of the leader will allow you to change leaders easily on stream. There is a right way and a wrong way to attach loop to loops:
Hope this helps.