Of course, I would just skip the whole animation part entirely, as things like treasure chests are sort of "background" items for the most part.

1) Anyway, as frosted_snow said, make an event with 2 pages with a switch activating the second page. Nothing TOO difficult, but if you need screenshots or something, ask away.

2) Tools -> Resource Manager, and click on "Graphics/Titles" on the left side. Then, choose Import on the right side. Titlescreens must be 640x480 pixels.

3) "Play Movie" was removed from RMXP, so it's RM2k3 only.

4) You don't, in RMXP.

5) Tree backdrop? If you mean the test battle background, just click on "Change Battle BG" in the Database/Monster Group tab when you're testing the battles. If you're talking about the battle background within the actual game, you can either set the battle background in the map properties or by setting up the terrain in the tileset (which isn't of much use unless it's a world map or something with multiple terrain types, so I won't go into it here unless you need help with it)