Let's recall, as well, that the Constitution Act, 1982, instructs the judiciary to render laws that are inconsistent with the Constitution of Canada to be of no force or effect--the power of judicial review, then, is demanded of the courts, and is not (contrary to what many people suggest) an invention of activism from the bench.
Judicial review, as it stands, merely opens the door to judicial activism, but they are two different things, as different as rendering unconstitutional laws to be of no force or effect, to reading into, or in fact writing into laws what you believe the law should be. As well, the courts and the courts alone decide which cases will be heard.
Besides, the principle of parliamentary supremacy is very much safeguarded in Canada, for four reasons here. One, s. 1 of the Canadian Charter of Rights and Freedoms (i.e., the "reasonable limits" clause) gives the Parliament of Canada the option of arguing that a restriction on a right or freedom is reasonable, in a way that is "justifiable in a free and democratic society." Second, s. 33 of the Charter (the notwithstanding clause) gives Parliament the ability to expressly override fundamental freedoms. Third, the Supreme Court Act is in fact an instrument of Parliament, and therefore the courts are inarguably subordinate to the legislature. Fourth, our honourable justices are accountable, for their conduct, to Parliament--the Honourable the Senate of Canada, and the House of Commons, may at any time jointly request that His Excellency remove a justice.
I know of only one case where a Supreme Court Justice was removed from the bench, he wasn't fired, but sent to a sort of judicial land of Nod. In any case, they may be accountable to parliament, but they are not accountable to the people.
Section 33 is a double edged sword, but it certainly isn't needed for parliament to override fundamental rights and freedoms, they can and have done just so because the Charter itself is full of enough holes to allow for it. The biggest hole is the one you mentioned first; what is not reasonable or not demonstrably justified today may well be made demonstrably justified tomorrow. Or, in the case of Bountiful, what is considered reasonable and demonstrably justified today may not be at the end of this thing, according to the courts that is.
Reasonability is as fluid as it is subjective, even what is demonstrably justified is open to interpretation. Many bad laws have been enacted where justification has been manufactured by lobbying, misrepresentation of statistics, or just plain emotion, but I digress.
Much emphasis has been placed on individual rights, but only to the extent to what is considered to be reasonable by "progressive" thinkers, (most of whom have a marked disconnect with reason and reality). This will eventually lead us, as a society to something that would have been unrecongnizable 30 years ago, in fact I think we already are, and its only about to get worse. Many believed that allowing gays to be legally married would somehow threaten the institution of traditional marriage. Nope, that train left the station when we allowed no fault divorce and recognized common law relationships. Whether recognizing plural marriages is the next step is going to be a crap shoot.
I don't hold out a whole lot of hope. FLDS members are indoctrinated from birth to believe "celestial marriages", (the term the FLDS prefers) are their doorway to Heaven; for the men, more wives = more favour. For the women, they will become goddesses in the afterlife. Wives are assigned to a husband by decree from the prophet. The women must be subservient and children obedient. The men own everything and the women own nothing. I'm not sure of the sect in Bountiful, but in Utah they were very strictly controlled, they had very little or no money. I many cases where they worked outside the family business all monies were turned over to the husband or dominant wife. Though women could drive, there were no plates on the vehicles. If they either ran out of gas or were caught with the unregistered vehicle they were simply returned to the home by police, (many of whom were either members or sympathizers of the FLDS), and often to some sort of sanction or beating.
A polygamy prosecution may be a tough row to hoe. Witnesses completely dependant upon the accused may not be too co-operative. Polygamy put Warren Jeffs on the radar, but it was tax evasion that brought him down, (along with the followers who believed he was ready to pass out the punch). What will happen with Bountiful is anyone's guess. Polygamy brings with it a boatload of societal ills, if it ends up being legitimized I fear for society as we know it.