Re: Using my customised WP theme in BBPress?
Yes you can however it is fiddly as it requires coding! It involves crafting a bbPress theme manually to make use of the same stylesheet and page structure as your WordPress theme. Your theme stylesheet will also need certain rules for bPress.
I found when developing my themes that bbPress will use template files from the default theme if they are non-existent in a theme. This means that you can keep the number of .php template files in the theme to a minimum of 3 php files for a 1 column theme or 5 php files for a 2 column theme (i.e. with sidebar).
If you had someone create your WordPress theme for you, then direct theme to bbpressraw.com since these themes are a bare-bones starting point for creating a new bbPress theme. They save some time in stripping down a bbPress theme to its bare essentials.