I'm not sure if I completely understand your question, but here is an overload of information, that I think is related.
Action Step Flags are set in NESmaker in the Object Details window under the Actions tab. I haven't messed with the Adventure module in 4.1, but here is what I understand the flags are set up to do in the Platformer module:
Action Flag 0: Ignore Main Physics: Honestly, I'm not sure what this is suppose to do. Most of the time it seems to just make objects move down and to the left for me and I haven't figured out how to change an object's behavior. The comments in the code seem to imply that this is for projectiles.
Action Flag 1: No Player Collision: Collisions with the player will be skipped.
Action Flag 2: Immune to Weapon: Collisions with objects flagged as weapons will be skipped.
Action Flag 3: Jump On Kills: Collisions with the player if the player in colliding from above will destroy the object.
Action Flag 4: Ignore Gravity: Disables vertical movement.
Action Flag 5: Not Defined
Action Flag 6: Not Defined
Action Flag 7: Ignore Solids: Object won't be stopped by solid tiles.
When an object switches action states, it will load these flag values from a look up table into Object_vulnerability.
When you said "Invincible," I'm not sure if you were talking about the No Player Collision, Immune to Weapon, or Jump On Kills flags, but there is another context in the code where invincibility comes up. This is when a player or monster has been hurt, and is invincible for a brief period of time. This invincibility is not stored in the object action flags or Object_vulnerabily variable, instead that is kept track by the Object_status variable. Here are what the bits of Object_status are used for that I have been able to determine:
Code:
Bits:
76543210
||||||||
|||||||+- Is the object Invincible?
||||||+-- Is the object Hurt?
|||||+--- If it is the player, Is the object on the ground? If it is not the player, is the object
||||| at the edge of the screen?
||||+---- Object has been reserved.
|||+------ Not Defined?
||+------ Object is scheduled to be deactivated.
|+------- Object is scheduled to be activated.
+-------- Is the object active?
Everything that I have talked about here is so far hard coded into the different scripts of the module. There is no easy way to change out what sort of effects the bits do because there might be several spots in the code where they are used.
And yeah, as far as I can tell "Spawn Type" and "Hurt Reaction" haven't been hooked up to the code yet. Same goes for "Jump Speed," "Experience," "Strength," and "Defense." I know how to hook up those last 3, but not the others.
I hope something here answered your question. Sorry if it was too much information.