1. Not sure where you are seeing accu-set, all I see says accu-choke. I believe accu-set is a fixed choke (usually sold in as Big 5 specials) accu-choke is the actual changeable choke.
2. The forend on a shotgun is the wooden piece. The tube underneath is merely the "tube".
This has a 24" barrel, depending on your use I would recommend a 28" (maybe a 26" but 28" is more of the standard.)
Also, the "Bantam" model is more of a youth model. Likely the stock is shorter, that's also why the forend is farther back, and the barrel is shorter.