[Nick_K]

The number of opponents is a matter for personal taste. As an extreme example, On the Dom1 demo I would often play with every land opponent except Ermor on the (small) Urgaia map.

Having 5 players for 45 provinces seems fine to me.

Dominions is quite hard at first, much more so than most strategy games. I think only MOO3 and Football Manager 2005 made me lose as much when I started. It's pretty normal to lose a lot at first.

You can call a pretender back with the 'call god' command. They appear at your capital once you've done it enough. The returned pretender will lose 1 level from each magic path. Some of the afflictions they had will be cured, but not necessarily all of them IIRC.
Your bless is not affected by this loss in magic.

With the demo you probably don't have time to win outright without a fairly dull rush strategy. For example:
Taking fire 9 / water 9 on your pretender gives a great bless.
Then take strong dominion, imprisoned (for points), death 3, sloth 3, drain 3 (points... don't need growth or magic with the time limit). Order 3 (for gold).
Build lots of your sacred melee guys. Put your prophet in charge and have him cast 'divine blessing'. Put them near the front of the battlefield and give them attack orders.
They will annihilate almost any independant or AI force you're likely to meet on a small map. poor against humans because they're very vulnerable to archers.
This is a quite dull tactic though... If you want to win you could try it but I doubt you'll find it interesting for long.
Sadly, the turn limit means that it's hard to win in the demo while using the fun stuff of dominions. With Kailisia in the full game you can summon Gandharvas - they are awesome!