Sodium nitrite, particularly in an acidic medium, reacts with primary amines, secondary amines, epoxides, and alcohols to give either nitrosamines or nitroalcohols. As an aside, sodium nitrite is also a component in the antidote for cyanide poisoning (the other component is sodium thiosulfate). I know of no synthetic utility for the reaction of nitrite with the other functional groups that you list, but there may well be side reactions.
Since you are concerned about selectivity, why not just stay away from reducing agents altogether? For example, to quench the hydrogen peroxide quickly, you could use a disproportionation catalyst. Consider manganese dioxide, Lindlar's catalyst, or even catalase enzyme (the latter will work in 50% acetonitrile/50% water). As for the hypochlorite, you can effectively quench it by adding an excess of cyanuric acid but this would make the solution acidic. However, I think that even cyanurate salts will react with free chlorine to effectively quench the hypochlorite. Depending on your solvent, you could also precipitate the excess perchlorate with lithium chloride, as is commonly done in the industrial synthesis of lithium perchlorate.
Please let us know how things work out! Good luck,
Nick Conley, Principal
Conley Chemical Consultingwww.conleychem.com