The game version should be the one where all the factions match the standard ones; otherwise, you'll be playing a different game and become a novice in it!!! Because knowing all the nuances of the game allows you to build your strategy.
Full Tech Tree (TE) is unacceptable for a player accustomed to the standard factions, especially for a tournament of this magnitude, as they may not have even seen it!!! (It might be suitable for casual play, as well as playing against Necropolis or against two opponents.)
Standard factions (SOD) and Light Tech Tree (TE) are suitable; you'll just need to get used to TE (the buttons), but at least everything will match the standard factions.
Template:
Are there any differences between random and fixed maps?
In fixed maps, there are pre-made layouts for each map, and deviating from them means you won't see victory!!! I've never played fixed maps and don't plan to; I don't want to play chess. (I didn't mean to offend fixed map players; it's just that random maps were initially planned here.)
For myself, I would play with any random template.
I accept any rules for myself, except for cartographers and various diplomacy options (not skill, but joining monsters), and possibly a lottery with scrolls (DD without building a Guildhall or having the right date).