Get a second opinion from a reputable shop that will explain things to you to your satisfaction.
If the pads are indeed 95% worn I wouldn’t try to go any 7,000 miles. A month ago was not too soon to replace them, and I think you’d be pushing your luck to put it off any longer than a month from now.
Overnight surface rust isn’t an issue here, and almost certainly is not what they were referring to. It’s not unusual for rotors to start rusting away on their edges, and sometimes it eats away a significant amount of the surface. In these cases resurfacing often won’t restore much of the eroded surface area before the rotor is too thin to use. It’s quite plausible that the rotors need to be replaced, but we can’t judge that from here. A good shop will evaluate them based on various factors including thickness, degree of warpage, and amount of rust erosion.
400 strikes me as high for this, assuming the job is strictly replacing front pads and rotors. My estimator shows 1.8 for this. For a dealership with a labor rate as indicated and using Honda parts, I would have expected about 325. It’s a pretty safe bet that a good independent shop can provide a top quality repair for less than the 400.
Factory parts are the benchmark for quality, but a fair portion of top-grade aftermarket parts equal or even exceed them. You can’t go wrong with factory parts, but sometimes you can do better with aftermarket ones.
But not all aftermarket parts are created equal. One of the problems with the aftermarket is that there are also options for poorer quality that cost less, and many people choose them based on price. In the long run, though, it often costs more to do it cheap.
I recommend selecting a good shop and letting them provide the entire repair. What’s the point of bringing the parts? The shop can get anything you can get. If you somehow get the wrong stuff, there are delays and hassles. It’s not likely to save you much, if any, money. And you’re in warranty limbo - if something goes wrong, you’re stuck in the middle between a parts supplier who might claim they were installed wrong and a service provider who might claim they were defective. I don’t see anything to be gained by bringing your own parts.
Since it’s been mentioned, I’ll clarify one aspect. This type of service (like most in auto repair) is priced by the job, not by the clock. You may hear or see references to “book time” or “hours,” but that’s industry jargon (sloppily used, because of the obvious potential for confusion) and does not purport to indicate billing by actual time spent.