There's a built-in way to do this (that has built-in balancing drawbacks) and a modding way.
To hide your name from other players, just sneak (crouch) the whole time you are trying to avoid detection. Your name won't show through blocks then, and even without blocks in the way it will be dimmed and harder to read.
The modding way is a Bukkit plugin called HeroSneak that will add a server command /sneak (along with persmissions hooks for who can use it, etc., so as usual you will need other mods if you want to restrict it). HeroSneak exploits the built-in way of hiding your name: it just activates the name-hiding feature with a command instead of tying it to whether or not you are crouching.
When summoning a LightningBolt with /summon, NBT input is ignored, so there is no NBT data you can provide.
As an alternative, 1.9 introduces a new block called the End Gateway, which produces beams of light similar to beacons. Unlike beacons, there is no need for a specific structure and the beam will go through all blocks (both upwards and downwards).
You could potentially setblock an end gateway at Y0 via /execute to produce the same sort of effect without damaging the player. The Age long tag for end gateways will create a magenta beam of light so long as the value is below 200, so you can use that to specify the duration the beam should last for.
/execute @p ~ ~ ~ /setblock ~ 0 ~ minecraft:end_gateway 0 replace {Age:160l}
Note that end gateway blocks will not teleport entities if the ExitPortal compound is not defined, but its beam will still become yellow if an entity enters it while Age is 200 or higher. If you wanted yellow beams instead of magenta, you could create the end gateway as well as summon an entity that will despawn after a set amount of time.
For example, the following creates an end gateway with an AreaEffectCloud entity inside it that will despawn after 100 ticks (5 seconds):
/execute @p ~ ~ ~ /setblock ~ 0 ~ minecraft:end_gateway 0 replace {Age:200l}
/execute @p ~ ~ ~ /summon AreaEffectCloud ~ 0 ~ {Duration:100}
Best Answer
Fireworks that were crafted with a firework star deal damage. The regular ones with just gunpowder and paper don't. The NBT tag that determines the damage is the same one as for the visual effects.