1.How to count the naval support of ships? Attack value goes during the support while attacking and defense value during the defending?
2.+1 naval combat increases only attack or defend also? It's counted only for the sea battles or during the naval support also?
3.When rival's capital or other city is capturated, which of the technolgy and amount of gold one's obtaines?
4.Spanish gold exploaration is only for discovered plains, forrests or barbarian villages too?
5.Would I receive +2 Napoleon's benefit for cannons if upgraded such unit type them to artillery?
6.How German Automatic tech upgrades for Elite units works?
7.By the way, after 3 wins unit(s) becomes veteran(+50% for A+D) and after six wins - elite and every 3 victories adding one more elite status/skill?
1.) It's always calculated as half of the ship/fleet's
attack value, rounded down to the nearest whole number. So a battleship fleet, that attacks at 54 but defends at 81, still only gives +27 naval support. Whether the friendly unit is attacking or defending is irrelevant, the naval support value is always the same. Also note that it's calculated off the final value of the naval unit giving the support, so fleets or veteran units give more naval support, and stacking bonuses like Spain/England's special era bonus with Samurai Castle's greatly improves the naval support of a veteran fleet of high attack boats like cruisers or battleships. Indeed, one of the potent strategies involving Spain exploits the significant amount of early game naval support that a fleet of veteran Galleons can give after they get their 5 tech bonus.
2.) Naval combat bonuses that the Spanish and English get count as a static +1 to the base power of the unit. This means it counts towards BOTH attack and defense, gets tripled in a fleet, and multiplied by the Veteran promotion. It does not directly increase naval support itself but the increase in the attack of the unit does so indirectly. As the bonus is quite small, you will only see a positive gain in naval support if you make a fleet so the bonus adds at least +3 to attack, which nets +1 naval support (3/2 = 1.5, rounded down).
3.) I'm not sure what determines these factors directly. You will tend to get the highest tech they have (Such as Code of Laws or Monarchy if you conquer Rome or England early) but it is possible to get a lower one and commonly none at all. You also will not get any tech you already have and the AI has to have it researched (so no freebie techs at random just for conquering, they must have the tech). As for gold that's fairly straightforward: you get larger amounts if they have more in their treasury, which you can see easily by capping cities in the scenario It's the Money That Matters, where everybody starts with 1000g.
4.) Only for named tiles you uncover (El Dorado Plain, Gibraltar Sea, etc.) when you move through them. It affects nothing else
5.) No, When the civ era bonuses mention specific units as opposed to a unit type in general, they mean only those units exactly. Only Cannons get the +2 attack bonus for Napoleon. Japan only gets +1 attack to Knights, not horsemen and not tanks, etc.
6.) The unit must be elite, meaning it has one of the promotions after Veteran. It only needs one Elite promotion, more does not matter. When you research the next technology in that unit type's tier, all of the elite units you have of the previous tier will automatically and instantly upgrade to the new unit. It only works at the EXACT MOMENT you finish the technology, so you cannot elite some units later and expect them to upgrade, and you cannot skip unit tiers. So if you have a whole bunch of Elite Legions sitting around waiting to upgrade but skip Feudalism and get Combustion first, they won't upgrade into Tanks, and even if you pick up Feudalism later, they will only upgrade to Knights because you missed the boat on Combustion, so to speak. The best way to leverage this ability is with a city that has a Barracks+Great General settled so you can produce Elite units at any time, or spam Warriors in the early stages out of cities with just a Barracks (German Warriors created with a Barracks start as Elite) and upgrade them all the way up, taking care to research the techs in order for each next tier.
The unit tiers are as follows:
Warrior (no tech) >>> Legion (Iron Working) >>> Knight (Feudalism) >>> Tank (Combustion). Horsemen are kind of the odd man out, Warriors do not upgrade to them and they do not upgrade to Legions, but Knights instead.
Archer (Bronze Working) >>> Pikeman (Democracy) >>> Rifleman (Gunpowder) >>> Modern Infantry (Mass Production)
Catapult (Mathematics) >>> Cannon (Metellurgy) >>> Artilliery (Automobile)
Naval units cannot upgrade this way for the Germans as they cannot become Elite, only Veteran. For the sake of completion, they can be upgraded with Leonardo's Workshop in a similar fashion, in which case the tiers are:
Galley (no tech) >>> Galleon (Navigation) >>> Cruiser (Steam Power).
Nothing upgrades into Battleships or Submarines, and Galleys upgrade directly into Cruisers if you already have Navigation and Steam Power when you build Leonardo's Workshop, as it upgrades units to the highest tier that you have completed all the lower tier techs for.
7.) Yes, this is the way it is supposed to work except for naval units, which can only become Veteran by being produced in a city with a Barracks. YOu can obtain every promotion on a single unit if you fight enough, but only the ones appropriate to the unit's type: attack or defense. Attacking units cannot get the defensive upgrades, namely Leadership, Loyalty and Engineer. Defense units cannot earn Blitz or Infiltration or Guerrilla, etc. Warriors count as an attacking unit for the purposes of promotions, but they can erect fortifications (indicating they are a defensive unit as well, oddly).
Note though that this is buggy and a lot of times you'll notice that your units stop earning promotions before they have the whole set. It's especially egregious when you're trying to earn a complementary set of promotions like Blitz+Infiltration on an attacking unit and it just stops getting promotions altogether. The only way I've seen to fix this (sometimes) is win a fight by being attacked by an enemy unit, which will then award the next promotion while showing you that it was tracking the number of combats all along!