1) You can have a splash screen with your own picture if desired. It can also be removed.
2) As has been said, multiplayer in FPSC isn't that great, there have been many debates about it already. Search for "Lemur" and go to the thread about the "Free" version, that will include some multiplayer additions, such as teams, and scriptable team matches. (So you can basically make up your own rules if you become good enough at scripting)
3) Search for "Sensei", it is a Allies script that was only compatible with Empty's Mod, and unfortunately, that mod was only compatible V1.0 of FPSC. I'm not quite sure, but it MIGHT also be compatible with a mod that I've written (known as "Ply's Scripting Mod").
If you can live with a simple multiplayer, and have the money for it, I'd suggest going for FPSC X10. It comes with much better allies, better default graphics, and many more goodies. (Although, a lot of those goodies are coming over to FPSC X9 soon with a migration that is being worked on)
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The one and only,
~PlystirE~