Is there any documentation for how to configure Plasma Widgets - especially Lancelot and Dictionary?

At the face of it, it seems that all Lancelot does is provide an alternative display of the standard K-menu, and any changes to one are reflected in the other. What I had hoped was to be able to build one or more, entirely separate menus, and maybe it is possible, but who knows?

The dictionary seems completely unconfigurable - it does something, sometimes, when I type in a word, just not what I want it to - which is to look up words in one more languages of my choice. Ideally I would configure it to look in several languages - eg. German, French, Italian, Dutch, ... - and the it would look for any word in all of those.

To my knowledge, there is no specific documentation available to aid in configuring them. At least for the Dictionary applet it seems it is only configurable if your system has the "qstardict" dataengine installed. As far as I can tell, this is not shipped as part of the KDE SC, and must be installed separately.