Is unlimited ammo possible?

In MTW it was possible to have unlimited ammo for archers, siege weapons and gunners. Is that possible in M2TW?

Also, what is the difference in the 3 type of battle screen cameras - Total War style, General's view, and RTS?

It is one of the options when you begin a new campaign. I don't remember all the differences except that all but one - IIRC it must be the Total War style you mention - frustrate me so badly that I can't stand to use them.

Afaik not when you start a campaign, but one of the options in the many files you can change.

In your base Medieval 2: Total War folder, there should be either a file called preferences.cfg, or a preferences folder with that inside it. (It might not be preferences.cfg but its close, so many medieval2preferences.cfg etc)

Inside that folder is all the options you can change, you can turn morale on and off, the green arrows, unit banners etc. The line you will want is:

unlimited_ammo = 0

Change that 0 to a 1 (Rome: Total War used False and True, Med 2: Total War uses 0 = False, 1 = True.) and you will have unlimited ammo for all ranged units!

I'm guessing that TW camera is the one where the upper parts of the sides of the screen are for rotating the view, and the lower parts to pan; general's view restricts the camera to what the general unit can see; and RTS is probably your bog standard top down view.

The biggest difference I've noted is in controlling the camera.

Left and Right arrow keys will rotate the camera, whereas mouse will move it, up and down arrow keys I am uncertain about.

RTS camera view uses the mouse to rotate left and right, arrow keys to move, mouse wheel to zoom in.