I am interested to know if I can add a scope, change powder and ball type, etc... just during a short range/ non-muzzleloader only season.
The caliber requirements for muzzleloaders specified on p76 still apply to the short-range weapons seasons, but otherwise, muzzleloader use during the short-range weapons seasons is not limited to the same restrictions specified for the muzzleloader only seasons.
That is, you could legally use a scope, sabotted bullets, Pelletized powder, closed ignition system, etc.
Please be cognizant of safety though. Many short range weapons hunts are in place to allow hunting where it would not be considered safe to allow use of regular rifle calibers. Although legal, Using a muzzleloader geared up to take shots in 200+ yd range may present safety issues.