Wow what frustration to see those BP10's go to another home
Def Tech makes great speakers, *especially* the BP tower series.
But you pretty much made up for it with the Leslie speaker find. It may not give you the same enduring pleasure as the BP10's would, but it should put a nice chunk of money in your pocket, and make some organ player happy!
Those MiniDiscs will probably be wanted by some radio station somewhere, that hasn't converted to computer audio yet. Put them on ebay and I bet you'll get some decent money for them.