Taffy's built-in bean factory only looks at /resources, so if you want CFCs from another folder, you'll have to use ColdSpring or DI/1. It's been a while since I last worked on or used it this way, but I know you can use both /resources *and* a 3rd party bean factory together, I just don't recall what the limitations are. Best I can offer right now is the documentation:
As for DI with tags, just use the <cfproperty> tag:
<cfproperty name="someBeanName" />
Then your code can reference it as this.someBeanName.foo(). Just remember that properties go into the THIS scope, not the VARIABLES scope.
HTH,
Adam