Mod: Questions for EA Gondolin Mod

[Tolkien]

Nation Description:

When the Noldor returned out of the Ancient West, they fought many Wars against the tyranny of the Prantokrator. Their princes built many great kingdoms and fought many battles in their wars against him, yet slowly, one by one, they fell beneath his onslaught, till only one, preserved in secrecy, remained. It is in Gondolin where the last Free Elves endure upon Beleriand, unchained, be they Noldorin or Sindarin. Guarded by the power of Ulmo, the Lord of Waters, by height of the Encircling Mountains, and by the vigilance of Eagles of Manwe, they thrived. Now, with the fall of the Prantokrator, they have returned out of the shadows of the past, to reclaim lands once theirs under the leadership of a new Herald out of Aman. The Gondolin is a great and marvelous city, famed for it's white walls, clear fountains, and green gardens. The Wardens of Gondolin stand guard upon the walls of the Seven Gates and maintain the secrecy of the City, and their hosts are arrayed in the Heraldry of the Twelve Houses of Gondolin.

Current Questions about modding and development
How would you mod a nation for an increased chance for heroes to appear?
How would you mod a multi-hero to have multiple, random, magic paths (like tarts), yet with restrictions to prevent them to have the magic levels stack in one path?
Any suggestions to allow for distinct differentiation between units of individual houses, as in skills and benefits, etc?
Is there a way to mod a magic site so that it autospawns units (in this case, Eagles), yet only does so for the starting nation (in this case, Gondolin)? Or would there be an easier way to go about this?
Should Earendil be a hero on his ship (and have flying, trampling, and size 6), or should he be made without it (and have Vingilot as an innate flying ship ability)? Also, what epithet should I give him? The Blessed, The Mariner, or The Morning Star?
Am I the only one frustrated with sprite-making?

Main thread:
http://forum.shrapnelgames.com/showthread.php?p=70294