2014,
Please don't take this the wrong way, but I'll be blunt. I graduated from KP last year ('09) so some of this stuff is still relatively fresh in my mind.
1) This kind of stuff would be the last thing on my mind when only mere days from Indoc. Spend as much time with your family and current friends as you can now because you are about to become VERY busy for the next four (maybe even five) years.
2) I personally do not like the new NWU and I think that mids would look horrible in them. I hope KP doesn't decide to have the mids wear these (and I'm not the only one to think so).
3) The new NWU only really replaces the wash khakis that was worn aboard ship. The "regular" khakis that KP mids wear is still worn by Navy personnel working in office/non-shipboard environments. This includes (I would imagine) the USN officers working in the Naval Science dept at KP. As KP2001 said though, it's more of a command-wide decision.
4) As was pointed out, the uniforms that KP mids wear are not official Navy uniforms (ie, the USN has absolutely no say in what KP mids wear - it's a KP-designed uniform that happens to be khakis). Physically, the shirts and slacks are the exact same brand and "model", if you will, as the USN but you wear different insignia that are unique to KP. Annapolis mids have their own uniform/insignia that is significantly different than KP. Every midshipman at KP wears the same uniform (except for some insignia), regardless of your post-graduation plans/commitment. Graduation/commissioning day is the first time that those going on to serve in other branches wear that uniform for the first official time.
5) Above all else, you are a midshipman at the U.S. Merchant Marine Academy. Yes, there are options outside of the "traditional" ones that KP grads follow, but KP is a maritime school first and foremost. It's not some quasi-backup-to-Annapolis/WP/CG/AF/USMC option school. Yes, there are mids who graduate into those services, but they all had to go through the exact same experiences that we all did and most of them didn't have an attitude about it. Those who bring in a serious "oo-rah" attitude may think they're all that, but the majority of the regiment will despise you (like I said, I'm being blunt). Those people also tend to not make it through, so be careful with how you handle yourself regarding that. My plebe-year roommate was kicked out because he thought it was more important to shine his shoes to a luster and "look sharper than everyone else", than to study for finals and actually pass his classes. Is avoiding a one minute dress-down more important than, say, graduating? You may think I'm exaggerating, but it's happened. Stuff like that is part of the test to see who has the skills required to make it through and beyond into the real world.
The regiment is small and tight-knit (only ~1000 mids, ~750 on campus), and most everybody knows who the ones are who think they're going to be the most "motivated" mid. Many have tried - most have failed.
Again, not trying to nail you down - just pointing out that you may want to tone down the hot-$^it attitude that I've read in a couple other threads too. I don't want you to become known as "that guy" during Indoc and the rest of your plebe year because it's hard to lose that label. I stayed under the radar during my plebe year and turned out just fine.
Enjoy the rest of your summer and try not to worry about stuff like this which you have absolutely no control over.