i forgot to mention that all streams (voice of the mics and video from the cams) have to be sent directly to a pc (the pc is the audio and video recorder). the presentation-system (which i will develop) will encode it and store it in the intranet of the university.
so a seperate audio recording no solution for the task.
the idea of the presentation-system is: switch on the devices, press record on a GUI, present your presentation, press stop and you have your presentation on your network-account

my problem is that i have not much experience with audio-systems. for example: shoudl i use a wireless or bluetooth mirco for the presentator? what are the differences?
if i need a pre amp, which one suits best to which micros?