Re: question #1 --
No, 'Combat to Hit DEC' is used to give an advantage for smaller ships, while 'Combat to Hit ADD' is used to give the disadvantage to bases. This does clarify why fighters have always seemed so wimpy, though. They are given a HUGE 'Combat to Hit Add' bonus with a description saying it increases their ability to HIT OTHER SHIPS. If this is the case, then bases also have a 'to-hit' bonus and not a bonus to BE hit, because it's the same ability used on bases. So, which way does this ability really work? Should they have "Combat to Hit Dec" with a negative value instead? Hmm...
As for your other questions: The Urban Pacification Center works fine, so the bonus is correct. Would be interesting to have a facility that INCREASED unrest, though. Maybe a genetic engineering facility that scared your population?
Troops have been able to land despite shields since SE3, so this is just as it has always been. The Weapon Family numbers are in the components.txt file with all the other information about the weapons. Read the ENTIRE entry for a weapon and you'll find it. Combat to Hit Add/Dec seems to affect the ship it is mounted on (or added to as a default). As a component ability the "Add" increases ability to hit the enemy -- Combat Sensors, while "Dec" decreases the enemy ability to hit you -- ECM. If these abilites don't work the same in VehicleSize.txt as they do in components, then fighters have been given a very large disadvantage for a long time, but if they do then bases have had an undocumented advantage. 'Combat Modifier - System' seems to work only for the Empire that owns the facility, so you want it to be positive.
We have asked before if various religious facilities, the Nature Shrine for example, will affect only your own planets, friendly planets, or all planets. Most of these "system wide" abilities need to be clarified.
Re: Wish #1 -- apparently the way ground combat works has been changed. It does not occur DURING ship combat anymore but during the strtegic phase of your turn. So, you drop as many troops as possible during ship attack, then wait to see the result as your turn is executed after you "end turn". I've got to drop some troops and try it myself soon.
[This message has been edited by Baron Munchausen (edited 27 November 2000).]