I have made a lightning strike effect by making a long narrow mesh with BF2's lightning texture on it. I then coded it to spawn in random places on the map at different angles. This was something I added to a night conversion of Victory Village in my BFHeroes'42 mod. So that part you should be able to achieve.
However I had attempted to have a sound effect tied to each lightning strike, but as of yet, haven't found away (using particles anyway). Sound scripts can't be tied to particle objects it seems. I could have the effect spawn a simpleobect/bundle instead, but I would lose the fading/size change effects associated with using a particle. So I still used particles.
As for the burning effect on the ground.....That would require that you rework completely how the effect works. Because your terrain will have hills and other changes in altitude, so having the effect spawn the burning effect/other effect on impact will be ineffective unless your map is completely flat and all one level. The move to water command for emitters only works for water. There is none for moving to the terrain. (which would have made this possible.

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You can try spawning lightning as PCOs via spawners at specific heights. But you would have to put quite a bit of them on the map for it to look realistic and not too artificial.
Oh also, if you want the lightning strike to actually harm soldiers on the ground you could make the lightning an obstacle object with a high damage value. (having it spawn as destroyed and with short timeToLiveAfter death so the lightning doesn't last long) That could be one way of achieving that. Though just as in real life, if you have an effective emitter for it that spawns it over a wide area randomly, the chances a player gets hit by one directly are just as slim as in real life.
