You will be able to use an AV new style Famicom in the US. You will NOT be able to use an older style one, because it has no AV plugs and the RF signal output will not display right on a US NTSC television set, period.

The Super Famicom needs the same AV plugs as the SNES (and N64 and Gamecube) so your existing ones will work fine. The AC adapter may not be included in the box, so make sure of it first. Technically, the US SF AC adapter will probably work with the Japanese system but I don't know whether or not they're fully 100% compatible.

Read: I don't want to be blamed for the heat death of your system.