No. None of this right.
1) Minx is designed to be a standalone 2.1, you will NOT be able to integrate it with any other speakers but its own
2) Pre AMP is exactly what it means, a connection PRE amp, or Before the Amp. So all you get is the signal, but none of the power. So the Minx has its own amplifier, therefore it would get connected via preamp. RS334 towers are 'passive' meaning that they do not have their own amplifier; therefore would connect to the Marantz speaker binding posts, which is powered by the Marantz's amplifier.
3) It is not advised to mix and match your speakers, especially the front 3. The main issue is having a different tweeter, if they are not of similar composition, you will likely hear an audible difference.
Audioholics provides many articles that I would urge you to read to expand your knowledge! You've got several good pieces of a system here, but have no idea what to do with them. Knowledge is power my friend!