All experience-bonus traits stack with each other. In your example is 85% therefore the correct answer. Trainer gives a bonus to the champion and everyone in the party. If you have several champions or henchmen with Trainer in the group, they will all stack.

I'm not sure what you mean with "skill with a shield". There are several traits with a shield-icon. Could you explain which one you mean?

never had the opportunity to build a legendary facility (for example Merchantcross Bazzar). and this despite the fact that I absorb Town lv up with the city. Legendary facilities are only for lv up?

Not necessarily. For example, Merchantcross Bazaar requires a Town and you need to have researched the tech Trading. Also, if anyone else has started to built the Bazaar, you can no longer build it yourself. There can be only one in the world. The Great Mill is similar, but it doesn't require a Town. You can build it in all city-types. This is the case with most World Wonders.

It is possible for a champion to get two or more Path-choices, but it is rare. In one of my games, I had chosen Path of the Mage for Procipinee and later could select Path of the Assassin. This happened twice to me since I joined during Beta 3.

Experience works different between champions and normal units. A champion receives full experience, while a units only receives half. If you have more than one champion in the group, the experience gets divided by the number of champions and the normal units receive half of that. Using your numbers, this would mean:

One champion 10 XP (+bonus XP from Potential, etc)

Two champions 5 XP (+bonus XP from Potential, etc) each

Three champions 3 XP (+bonus XP from Potential, etc) each

One champion and three normal units 10 XP (+bonus XP from Potential, etc) for the champion and 5 XP for each of the units

Two champions and three normal units 5 XP (+bonus XP from Potential, etc) for each of the champions and 3 XP for each of the units

I hope this explains it. 

So beneficial to go with the army - 1 champion and many units.

Yes, dead group-members return, if at least one member of the unit survives, even if you don't have the necessary resources to train them.

Yes, if you have a squad that's been depleted down to 2 out of 5 men, each with 8 hps, and you cast heal for 12 points, you will end up with 4 men in your squad, three with 8 hps and one with 4.

For your second question, it is kind of counter-intuitive.   Assuming a full squad, you will actually get +15 fire damage, but no matter how many men you have left in the injured squad, you will still only be healing 1 hps.  I guess the idea is that only one guy is injured, and only his amulet is working.  Don't ask me how men come back in combat.

About treatment. The game has a spell in the group beating? That is damaging to high (the more people in the group, the more damage)? If there is, in theory regeneration and poison should work the same way.

bonuses after lv up - random? that is, there is no clear list for a particular character (the list is generated at the start of the game)?

What is the fastest tactic to up the city? Outpost to build improvements on growth?
considered growth? there is in fact a basic tile. and then there are structures that give a bonus to the tile - as I understand, it's a bonus for all the tiles of influence of the city? or is it just built up bonus tiles?

there are better yielding gain per turn. I understand the growth - the number of people. that is, each turn added a pair of people (if you build a tower of dominion and similar buildings with a 0.5 increase). and all other facilities - do not give a rate per turn (those that increase the gain from the tile) - they just raise their bar?

Which units 5 points of movement? Once seen the AI champion with 5 points of movement.

I think that there are patches on what that certain levels

or all of the drop rate is reduced to:

rare
uncommon
common

it was magic)

http://s60.radikal.ru/i170/1210/84/ef792fb21bd1.jpg

surprising that the AI is just two ways. Way assassin. Way of the Warrior. Imposobl AI.

http://s017.radikal.ru/i435/1210/40/07f50958fe1f.jpg

yes

what type of card you must choose not to have any water? I love the very large maps. And sorry, if water is a decent part of the map. Mean sea.

how to allocate skills and magic to the hotkeys for tactical combat?

I once found a sort of boots +1 movement.  With +2 of horse +2 normal movement = 5 points of movement.

Maybe there is some equip that gives more movement...