You make a good point. It looks likely he had a "handler" who supplied the stuff and info the shooter needed.
Also, it was earlier reported the shooter was of Algerian decent, which would make him not so much of a "convert".
Also, would he be the kind of planner that would know this was the day that the weekly caucuses met, when both parties would gather in their respective rooms, at the same time? He seemed to know where the highest concentration of lawmakers were meeting. And for effect, that would be extreme terrorism.
And being French and Algerian, might make him hostile to the Ottawan government, and he would have been chosen because the drug-addled, have long been used as tools, pliable for violence and suicide.