Alot of the stuff you’re wanting can be solved with the Compositing Nodes Editor. For almost any video FX in blender, you’ll want to use this.
The Flash and Clash would have to be done After the blades are made. It would need to be post-processed. This can be done in the Nodes editor.
(This is based on you knowing at least a little about nodes. If you don’t, go HERE.)
For the Flash, All you need to do is set up your video, add an RBG color (white is recommended) Add a Time node. None of these are connected. Add a mix node. In the time node, Set the whole curve flat at the very bottom. Set the number of frames in your time node to correspond with your video. Link the Time node into your mix’s Factor slot. Insert your video ond your RBG into the mix node. At any point you want the Flash to occur, mearly drag a single new point inside of the Time node up as far as possible. I’d give you pics and stuff but yet again, I don’t have blender on me. Sorry. I’ll try to put up a quick tut on this as well later.
When you have a blade go behind another object, You’ll need to use a matte in the compositing node editor. For more info on mattes, go HERE (Yes it was made by WuMan)
The clash thing is also pretty easy once you get a hang of the nodes editor. You can make a quick video in Blender of a single Halo Flashing once. You just add this over your video in the compositing nodes editor at the right points, and Voila! the clash.
Again the Fanning can be done in the nodes editor. It’s a little complex so I won’t go into it here. Fourtunatly I’m currently working on compiling a large collection of methods for doing lightsabers and creating one large Tut on all the different ways. I’ll go ahead and add these to my set of ways. I’ll send you and anyone else who wants it a PM once the tut is finished.