Some questions on demo walkthrough

[LintMan]

Hello, I'm currently playing the demo walkthrough game, about 30 turns or so in. (Ie: I'm past the walkthrough part).

Some questions:

1) I discovered the Golden Naga god all by its lonesome in a province to the southeast, and attacked with my (Gode) Prophet, a Herse commander and about 15-20 javeliners, huskarls, etc. It seems as though my commanders never showed up at the battle, just the squad. (If the commanders showed up, they weren't in their normal positions). After my giants pounded on the naga to maybe half strength, they all fled despite zero casualties. Then, next turn I rounded up my troops and re-attacked, with the same results: no apparent commanders, and my troops retreated after getting the Naga 1/3 down on health, with no losses on either side. Any explanations?

2) Is there any way for me to reasonably quickly build up an underwater-capable force to try to take some of the water provinces. My pretender is water-8/earth-4, so I'd think that should a fairly reasonable thing, but I don't see many spells that will help. Is Nifelheim (is that the giants race's name?) a bad one to play for any underwater capability, or do I have the wrong set of magic skills? (Or am I just missing the possibilities?)

3) How many mage-type units is a good amount to dedicate to research, rituals/summoning, and gem site searching? At about 30 turns in, if I dedicate all my mages to research, I get about 32 res/turn. Is that good or bad? I'd like more, so use for summons and searching as well, but the mages, costing 250 each, will have a very large upkeep, won't they? Site searching seems to be a painfully slow process, particularly like in my case, where I'm using my Pretender to lead a fighting force.

4) What controls the number of provinces a unit can move in a turn? Sometimes, it seems my 2-move unit can move 2 provinces to get to certain ones, but only 1 province in another direction. Do nearby (but not blocking) enemy provinces matter for this? In another case, I noted one of my priests was able to move 2 provinces, while another priest could only move 1 province. Neither had any troops assigned, and neither was near any enemy provinces.