First, your Railgun has a DR rating which is simply too high. I mean sure, your weapons are made of strong metals, but can your shell's velocity do the same? Your railgun is said to be simple, so that is unlikely. If it were a DR 6, it would have a velocity and heat which could vaporize everything around it, if the weapon were used in atmosphere.
Your sword vibrating to do more damage is possible, though not DR 7 worthy. I may let it slide if you add some sort of energy component to the blade to aid it.
Also, given just how far it would advance Nepleslian technology, I would like a seperate submission for the Nano-Constructor layer. I want to know how they observed the technology in Maras, and how they obtained the data necessary to make this. I also wish to know just how much power it has.
Keep in mind that Maras couldn't just "make" weapons so much as integrate existing ones into its hull, and the speed it generates your plasma weapon is still frightening in comparison to its complexity and output. The fact it can generate metals of such density at such high speed is also enough to warrant more investigation.