Civilization – What do “Player Score” & “Military Strength” mean under Domination Victory

The difficulty bonuses for Civ are described on this wiki page. In general the game difficulty works such that

• Anything below prince gives you a bonus
• Prince gives no bonuses to anyone
• Above prince gives bonuses to the AI

I don't wan't to copy-paste all the values here (there are a lot), but I'll mention that the values being modified are:

• Science
• Culture
• Production
• Gold
• Faith
• Combat
• Research boosts
• Starting units
• Barbarian camp plunder yields

The extra 4 faith is probably from envoys at religious city states. If you have 3 envoys at a religious city state, you get +2 faith per holy site. If you have 6 envoys at a religious city state, you get an additional +2 faith per holy site (for a total of 4).

So, your 6 would be 1 for the mountain, 1 for the sacred path rainforest, and 4 for city states.

Also, while districts in other cities count for the adjacency bonus, there are no half points for adjacency bonuses that require 2 adjacent tiles. And also, you cannot combine 2 different bonuses. For example, with holy sites, 1 adjacent forest and 1 adjacent district gets you 0 faith in adjacency.