Slate did not find that out.
The truth is that the same man set up both events...at different times, but in the exact same location and that members of the kkk group attended the first event.
My impression was that all we have is Scalise attending a troublesome event, knowing it was troublesome, and constructing plausible deniability ahead of time.
I believe you have it right.
Scalise has to go. Boehner has to go.
Independently of this, Boehner needs to go, and Scalise for supporting Boehner. With this as icing on the cake, they both need to go times ten.
Too complicated. More likely a time- and money-saving event for his neighbor and some of the attendees. I think we're making way too much of this. We have actual communists in political office (deBlasio, a large number of Democrats and the entire Congressional Black Caucus), and we're worried about a peripheral association Scalise had with his neighbor's hobbyhorse? While we may not want to adopt the conservative equivalent of the left's "no enemies to the left (of us)", engaging in a witch hunt over something like this is excessive.