You'll find a few of us kayak fishermen here, but more over at NWKA.
You are, however, seeking singular answers to very broad questions.
A good all around rod would be a medium action spinning rod in the 7.5' range, rated for 4-18# or such. It would really be more of a short steelhead rod, but can do a lot. Ok for bass, way overkill for trout or panfish. Insufficient for salmon or sturgeon, short and a bit light for surf perch but could be made to work. Ok as a bottomfishing rod in the bay. Of course it will do a lot of things, just poorly. But a good place to start.
Kayak fishing around Portland ? The Willamette, any number of lakes, including Hagg. Ponds galore. The Columbia, with the right experience. Sauvie Island.
Is it safe ? Sure, if you learn what you are doing and don't take on more than your skills and gear allow.
No single store gets all my business. I would guess Fisherman's gets the lions share of my business, followed by bi-mart. From there it falls off sharply to include Fish 'n Field, Cabelas, Dick's, Sportsman's, and even Wally World. Lead sinkers are lead.
Tell us a little more about what kind of fishing interests you (is it only salmon ?) and you'll get more helpful guidance.