Impossible to answer without a detailed description of all markings, including who made it.
Many of the items are worth around $30 each. The exact amount will depend upon its condition and how it is being displayed.
Not a commemorative, but more of a limited edition. Doesn't really hold any more value than the standard model unless it is absolutely new in the box with all accompanying paperwork. Figure $200-$250. sales@countrygunsmith.net
It is the exact same rifle as the Glenfield Model 30A, and yes parts are the same as the Marlin 336. Forearm is the cap style.