Hey Omegamer, for the first point I'd recommend you take a look at the cutscenes and intro's from this game here:
http://forum.thegamecreators.com/?m=forum_view&t=204195&b=35&p=0
I don't believe you'd need to be an awesome artist to accomplish this. Me being rather un-arty could design something along these lines with enough effort. As well as that, consider having scripted events. Just try around with sound effects, post effects, different player camera angles, or perhaps use a video recording of in game to show how the player got to be where they were.
An example that springs to mind is the old wake up on the floor blinking slowly with a blurry screen, slowly regaining vision and focus. After getting up, the game will cue some audio expressing confusion etc etc. Something like that would be perfectly scriptable, but may take some looking into scripting commands to work. (For example I couldn't do that off of the top of my head, I'd need to read about player camera angles).
The intro off of Sem SaĆda would have to be the best FPSC intro I've seen, it briefly but completely explains why/when/where and gives the game some good boots to stand on.
I have less to ramble on about for the second point, but if you haven't already you should look at:
http://forum.thegamecreators.com/?m=forum_view&t=186371&b=21, wolfs guide to lightmapping. 50 is very high for light mapping quality (at least for me) and perhaps you should reduce that.
From memory texturesize works best at 1024, because for some reason it builds using less memory. So lower lightmapping quality and 1024 lightmapping texture may already help.
Which version of FPSC are you using? This may have something to do with it. There's not a lot else I can help with, I'm not a memory cap expert.
Few - that's all I have to say. Hopefully I helped somewhat.

- An Instinctive Fear IndieDB page, download demo today!