Questions about how experience is gained

[WhYdOyOuThInKtHaThApPeNeD]

Do you get experience for killing enemy units that are summoned? Such as units summoned by a Friendly Gremlin. So if the Gremlin summons more enemies during battle do you get more XP for that battle than if you killed just what the battle started with? Also enemy thorns summoned by Royal and by each other, Demonologist, Druid, Dryad, etc.

Also, do you get more experience from a battle if you have fewer stacks of units. Meaning if I enter a battle with just 1 stack of Black Dragons and win do I get more XP than if I entered with the full set of 5 stacks?

Also does the power of your army ratio to the power of enemy army affect XP at all? Meaning if I've got a really weak army but defeat a powerful force do i get more, as opposed to if I've got a massive army and kill off just a few bears.

Does anyone know of any variable factors that affect the XP gained from battles?