This is too broad. The mayor’s personal interests are not irrelevant to any judgment of his actions. For example, whether the mayor has a personal interest is relevant to a conclusion that the mayor is motivated by personal interest. What the mayor's personal interest would be irrelevant to is a conclusion about whether the legislation concerning fees is a good or bad policy. But the author's argument doesn't conclude that the legislation is good or bad or that we should or should not vote for the legislation.

This describes how the argument fails to establish that the mayor’s actions are actually sacrificing the interests of the city. The financial interests of the mayor’s family have no bearing on whether development fees are good for the city or not. The mayor's action might be in the city's interest even if it also happens to serve his own interests.

This is irrelevant. The mayor could be sacrificing the interests of the city for personal gain regardless of whether the council member has an interest in the matter or not.

This is irrelevant. The council member never invokes the city’s right to anything, so proving that the city has any particular rights is unnecessary.

This wouldn’t affect the conclusion. The council member claims that the city’s interests are being sacrificed in favor of the mayor’s, which could still be true even if the mayor’s need is equally desperate.