Right... Firearms... But I don't see anything that would prohibit one from carrying some bird shot in a pocket while slug hunting for deer for instance. Or using a Hammond game getter on a rabbit whe moose hunting.
Furthermore, when it comes to the firearms, judging by the rest of the paragraph, it would seem that the SPIRIT of the regulation is to prevent scaling up, not down. The example given is to prevent someone from carrying a rifle during a bows only season.
Not sure about the two firearms part... But with respect to what you said above, there's a calibre restriction portion that limits you to a minimum of 0.275 calibre when both small and large game seasons overlap... Have to read the regs again to see what is said of shotshells