1) In the enter message window you type
N[n]
But you replace the lowercase n with the number of the actor in the actor tab in the database.
2) There's really no easy way to figure this out. Or at least not that I know of. You're best bet is that, when you get completely done with an area, go in and playtest it, then tweak the EXP (required for a level, or given out by monsters) if necessary.
3) Yes, But you'll probably have to use a script. Though I don't think I've ever seen one that can do that.
4) Yes, there are several places. In the
Resources, Scripts, Tutorials subforum of the guild here, there is a stickied topic named "Holy Links, Batman!" that provides links to various RPG Maker related sites.
5) Yes, but you have to use a script. There are several available, but I'm afraid I havn't used any yet, so I don't know how they really work, you'll have to wait for someone else.
6) You create an event on the map, change it's sprite to the one you want, and it appears when you go into the game to test/play.
7) Yes, but it also requires a script. Of which, there are several available. The stickied topic I mentioned earlier has links to sites that have scripts too. Personally, I'd reccomend looking at
Creation Asylum.
8. The main actor will always appear on the map. If you want other actors to appear, you'll have to make events and give them the sprites of the actors.
I'm not 100% sure if the N[n] thing will work in VX, but if it doesn't, check VX's help file, and look for a topic titled "Events" and look through there. Provided of course it has one. I've never used VX.