This enhancement is really fun to play.Great enhancement of the engine :)

For the record: the spawn powers are 133, 134, 137

However I'd like to start a discussion on a few things: (I'll defend the way zangband implements pets, as it is a really enjoyable game, despite lacking graphics)

• Should the hero receive exp for minions killing enemies? Would it make sense to have it configurable?
  I'd disable that on default, as the minions are only helpers to get your way through the lands, not your exp source.
• Spawning multiple minions, these stand on each other, as there is no collision detection for other minions,
  Should the minions have collision?
  I'd do so as minions just come not only with advantages, but also disadvantages, hence operating in small caves may be hard.
• Currently the pets seem to "stay close / follow the hero" Other possible options(copied from zangband) may be:
   a) Stay close                                                                                                                
  *b) Follow me                                                                  
   c) Seek and destroy                                                                                                            
   d) Give me space                                                               
   e) Stay away                                                                   
   f) pets may not open doors                                                                                                    
   g) pets may not pick up items                                                                                                 
   h) Display current pets                                                                                                       
      Dismiss pets
• Combining the minions in the current implementation with stealth gives fun effects. The enemies seem to detect only the hero as an aggressor, but not the minions, so the minions could stand on an enemy without action to be seen.
• Another point to consider: will the minions stay minions forever? If I hurt them by accident such as with fireball, freeze or by a bow, they may turn into enemies as well?

I do not remember more content from 0.15 to 0.17, but there is definitely more content in the upcoming 0.18 :)

So transforming into enemies is not yet there storywise in flare-game.
However you can edit your save file, which is usually found at  ~/.local/share/flare/save[1..4].txt (for linux). 
Look out for line actionbar=<numbers> and replace one number (better take a 0) by 135.
This will give you the powre to transform into an antlion freezer for 5 seconds.

As said storywise ther is no use of transforms in flare-game. Maybe you want to try out polymorphable or concordia, which do use this feature in the stories.

As interested as I would be in seeing Flare as the subject of a research project like this, I'd actually recommend *against* it. I love Flare, but I doubt it's what you're looking for.

I can second this. You may have a look at http://manasource.org/ which is a Client/Server based approach (so multiplayer/networking is there) Lua is used as the scripting language for the server, so you can do branches, loops etc. The client software is quite developed, the server has been used only once so far in http://www.sourceoftales.org/ (The current running server is from 6 mothes ago, with some bugs :/ due to judgeing the lpc is late. (http://lpc.opengameart.org/) so rather checkout the latest versions for testing if it meets your requirements)