Please search the forums before posting to ask a question.
Your questions have been answered elsewhere in this board a few times.
For a summary:
- No, you may only have one level in a multiplayer game without using a Mod designed to support multilevel MP games. And even the Mods that support it are pretty restrictive. Closest I've seen so far is one that just loads up different built MP maps, which isn't very filesize efficient.
- No, unless you're using a Mod or hacking into FPSC's stored memory during gameplay. Same as above pretty much.
The one and only,