Those “steps” are for using the buddypress code, ie xml-rpc communication inside of groups. If you theme the general bbpress install to match your buddypress site then you won’t need to enable xmlrpc on the general site, just do the intergration.
I think someone will develop a modification of the groups, to be a general group pretty soon. If this is the case, then you would need to do those steps for both bbpress installs.
Hope that makes sense,