First of all, the Homebrew Channel does not allow you to play backups on your Wii. It is meant to allow you to install WAD files such as WiiWare and VC games, as well as many other homebrew apps.
You do not need to delete the channel before installing the chip. One thing has nothing to do with the other. The chip allows you to play burned games. the HBC allows you to install and use homebrew on your Wii. That's what it boils down to.
As far as I know you can play different region games with the Wasabi chip, but you have to be careful not to apply an update from a different region disc to your Wii, because that will cause problems, including semi-bricking your Wii. It's best to stick with your own region games, unless there's a game you want to play that wasn't released in the USA. To prevent the possibility of accidentally updating your Wii with a foreign update, use a brick blocker before burning any games from a region other than your home region.