So this isn't an issue with the Famicom or is it?
I'm getting the Famicom cart for my Famicom and I'm unsure.
Famicom has native support for the expansion audio so you're good, assuming it's a real Gimmick. 
Ok assume all I have is the rom, the N8 and an AV Famicom. Am I set?
Well you said "the Famicom cart" so I assumed you meant the game. Be sure to install the updated sound mapper posted above in the appropriate folder.
I don't understand much of what's going on, this just seems like the only problem game and I would like to figure out how to get it going before my cart arrives.
You will need to download the OS for Everdrive N8 and install to the root directory of the microSD card. Then take the Sunsoft mapper file posted in the OP of this thread, and drag it into the folder that contains the mapper files. All files must be unzipped. If you get a .zip, you'll need to extract it first. When prompted, select "yes" to overwrite the old file with the new one.
Next, create a new folder for your ROMs. These have a .nes extension. If you don't know where to get them, use a search engine but don't post requests here. It is not recommended to dump tons of ROMs in the root directory. If you have more than 250 ROMs, you'll need to split them into separate folders since the Everdrive software cannot read more than 252 files/folders per directory. I generally use alphabet but you can also manually create folders to sort games by genre, region or any other metric you choose.
Hope this helps.