1: Yes, they do stack. But you add all bonuses before you multiply so its 60 %
2: Fate Shrine 3 has the same Happines modifier as Urban pacification center 3. These do not stack. (check facilities.txt for info on facilities)
3: I can't. But what do I know, I'm just a barbarian
4: ??? If you send your suicidal scout, you can see everything in "Combat replay" in simultanious games and in tactical combat in sequntial. I have never had enemy units disaper from the enemy design window, strange. Later in the game you can develop scanners, should work nicly on sat stacks.
5: Fighters defending a warphole almost always move before they fire their first shot, giving your attacking PDC's a chance to fire first. I think I have tried every setting in the book, but I can't manage to get fighter to fire first and then move.
Hope this help.